The Centre de coopération internationale en recherche agronomique pour le développement (CIRAD) is a French research organization that specializes in agriculture in the tropics and subtropics. It is a state-owned body and it was established in 1984 following the consolidation of French agricultural, veterinary, forestry, and food technology research organizations for the tropics and subtropics.
CIRAD’s mission is to contribute to the economic development of these regions through research, experiments, training, and dissemination of scientific and technical information.
The Centre employs 1800 persons, including 900 senior staff, who work in about 50 countries. Its budget amounts to approximately 1 billion French francs, more than half of which is derived from public funds.
CIRAD is made up of seven departments: CIRAD-CA (annual crops), CIRAD-CP (tree crops), CIRAD-FLHOR (fruit and horticultural crops), CIRAD-EMVT (livestock production and veterinary medicine), CIRAD-Fôret (forestry), CIRAD-SAR (food technology and rural systems), and CIRAD-GERDAT (management, common services and laboratories, documentation). CIRAD operates through its own research centres, national agricultural research systems, or development projects.
The International Center for Tropical Agriculture (CIAT, its Spanish acronym) is dedicated to the alleviation of hunger and poverty in developing countries of the tropics. CIAT applies science to agriculture to increase food production while sustaining the natural resource base.
CIAT is one of 16 international agricultural research centers sponsored by the Consultative Group on International Agricultural Research (CGIAR).
The Center’s core budget is financed by 27 donor countries, international and regional development organizations, and private foundations. In 1996, the donor countries include Australia, Belgium, Brazil, Canada, China, Colombia, Denmark, France, Germany, Japan, Mexico, the Netherlands, Norway, Spain, Sweden, Switzerland, the United Kingdom, and the United States of America. Donor organizations include the European Union (EU), the Ford Foundation, the Inter-American Development Bank (IDB), the International Development Research Centre (IDRC), the International Fund for Agricultural Development (IFAD), the Nippon Foundation, the Rockefeller Foundation, the United Nations Development Programme (UNDP), and the World Bank.
Information and conclusions reported in this document do not necessarily reflect the position of any donor agency. Cassava Flour and Starch: Progress in Research and Development
Centre de coopération internationale en recherche agronomique pour le développement, Département des systèmes agroalimentaires et ruraux 73, avenue Jean-François Breton BP 5035 34032 Montpellier Cedex 1, France
Centro Internacional de Agricultura Tropical International Center for Tropical Agriculture Apartado Aéreo 6713 Cali, Colombia
CIAT Publication No. 271 ISBN 958-9439-88-8 Press run: 1,000 Printed in Colombia December 1996
Cassava flour and starch : progress in research and development / D. Dufour, G.M. O’Brien, Rupert Best. -- Montpellier, France : Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Département des Systèmes Agroalimentaires et Ruraux ; Cali, Colombia : Centro Internacional de Agricultura Tropical, 1996. 409 p. -- (CIAT publication ; no. 271) ISBN 958-9439-88-8
1. Cassava -- Flour. 2. Cassava -- Starch. 3. Cassava -- Cassava as food. 4. Cassava -- Research. 5. Cassava -- Action research. I. O’Brien, G.M. II. Best, Rupert. III. Centre de Coopération Internationale en Recherche Agronomique pour le Développement. IV. Centro Internacional de Agricultura Tropical.
Copyright CIAT 2002. All rights reserved
CIAT encourages wide dissemination of its printed and electronic publications for maximum public benefit. Thus, in most cases colleagues working in research and development should feel free to use CIAT materials for noncommercial purposes. However, the Center prohibits modification of these materials, and we expect to receive due credit. Though CIAT prepares its publications with considerable care, the Center does not guarantee their accuracy and completeness.
ii Contents
CCCONTENTS
CONTENTS
Page
Forewordix
Preface Dany Griffon and Rupert Best xi
SESSION 1: INTRODUCTION
Chapter 1 Adding Value to Products, Byproducts, and Waste Products of Small and Medium-Scale Cassava-Processing Industries Dany Griffon 3
2 CORAF Networks G. Hainnaux 6
3 The Cassava Biotechnology Network and Biotechnologies for Improving the Processing Quality of Cassava A. M. Thro, W. M. Roca, and G. Henry 10
SESSION 2: CURRENT USE AND FUTURE POTENTIAL
Chapter 4 Starch Potential in Brazil M. P. Cereda, I. C. Takitane, G. Chuzel, and O. Vilpoux 19
5 Producing Cassava Flour in Peru and Its Prospects for Development S. Salas Domínguez, Y. Guzmán, and S. Aquino 25
6 Cassava Starch in Northern Cauca, Colombia: Socioeconomic Evaluation of Its Production and Commerce Liliana Mosquera P., Myriam Patricia Chacón P., G. Henry, and G. Chuzel 30
iii Cassava Flour and Starch: Progress in Research and Development
Page
Chapter 7 Cassava Starch and Flour in Ecuador: Its Commercialization and Use Carlos Egüez 42
8 Cassava Products for Food and Chemical Industries: China Jin Shu-Ren 48
9 Thai Cassava Starch Industry: Its Current Status and Potential Future Boonjit Titapiwatanakun 55
10 Sweetpotato Flour and Starch: Its Uses and Future Potential Nelly Espínola 71
11 Prospects for Cassava Starch in Vietnam Dang Thanh Ha, Le Cong Tru, and G. Henry 78
12 Cassava Flour Processing and Marketing in Indonesia D. S. Damardjati, S. Widowati, T. Bottema, and G. Henry 89
13 World Production and Marketing of Starch Carlos F. Ostertag 105
SESSION 3: PHYSICOCHEMICAL STUDIES OF FLOURS AND STARCHES
Chapter 14 The Role of Common Salt in Maintaining Hot-Paste Viscosity of Cassava Starch O. Safo-Kantanka and Rita Acquistucci 123
15 Amylographic Performance of Cassava Starch Subjected to Extrusion Cooking Z. González and E. Pérez 128
16 Improving the Bread-Making Potential of Cassava Sour Starch D. Dufour, S. Larsonneur, F. Alarcón, C. Brabet, and G. Chuzel 133
17 Physicochemical Properties of Cassava Sour Starch C. Mestres, X. Rouau, N. Zakhia, and C. Brabet 143
18 Influence of Gelatinization Characteristics of Cassava Starch and Flour on the Textural Properties of Some Food Products S. N. Moorthy, J. Rickard, and J. M. V. Blanshard 150
iv Contents
Page
Chapter 19 Two Rapid Assays for Cyanogens in Cassava: Their Evaluation, Modification, and Comparison G. M. O’Brien and C. C. Wheatley 156
20 Acute Poisoning in Tanzania: The Role of Insufficiently Processed Cassava Roots N. L. V. Mlingi 166
21 Gari, A Traditional Cassava Semolina in West Africa: Its Stability and Shelf Life and the Role of Water N. Zakhia, G. Chuzel, and Dany Griffon 176
SESSION 4: BIOCONVERSION AND BYPRODUCT USE
Chapter 22 Fermentation in Cassava Bioconversion M. Raimbault, C. Ramírez Toro, E. Giraud, C. Soccol, and G. Saucedo 187
23 Cassava Lactic Fermentation in Central Africa: Microbiological and Biochemical Aspects A. Brauman, S. Kéléke, M. Malonga, O. Mavoungou, F. Ampe, and E. Miambi 197
24 A Lactic Acid Bacterium with Potential Application in Cassava Fermentation E. Giraud, A. Brauman, S. Kéléke, L. Gosselin, and M. Raimbault 210
25 Cassava Wastes: Their Characterization, and Uses and Treatment in Brazil M. P. Cereda and M. Takahashi 221
26 Cassava Starch Extraction: A Typical Rural Agroindustry with a High Contamination Potential Olga Rojas Ch., Patricia Torres L., Didier Alazard, Jean-Luc Farinet, and María del Carmen Z. de Cardoso 233
SESSION 5: TECHNOLOGY DEVELOPMENT
Chapter 27 Improving Cassava Sour Starch Quality in Colombia C. Brabet, G. Chuzel, D. Dufour, M. Raimbault, and J. Giraud 241
v Cassava Flour and Starch: Progress in Research and Development
Page
Chapter 28 Investigating Sour Starch Production in Brazil R. C. Marder, R. de Araujo Cruz, M. A. Moreno, A. Curran, and D. S. Trim 247
29 Implementing Technological Innovations in Cassava Flour and Starch Processing: A Case Study in Ecuador Vicente Ruiz 259
30 The Influence of Variety and Processing on the Physicochemical and Functional Properties of Cassava Starch and Flour A. Fernández, J. Wenham, D. Dufour, and C. C. Wheatley 263
31 Establishing and Operating a Cassava Flour Plant on the Atlantic Coast of Colombia Francisco Figueroa 270
32 Improving Processing Technologies for High-Quality Cassava Flour D. M. Jones, D. S. Trim, and C. C. Wheatley 276
33 Cassava Flour in Malawi: Processing, Quality, and Uses J. D. Kalenga Saka 289
SESSION 6: NEW PRODUCTS
Chapter 34 The Potential for New Cassava Products in Brazil G. Chuzel, N. Zakhia, and M. P. Cereda 299
35 Extrusion Processing of Cassava: Formulation of Snacks N. Badrie and W. A. Mellowes 304
36 Thai Cassava Flour and Starch Industries for Food Uses: Research and Development Saipin Maneepun 312
37 Yuca Rava and Yuca Porridge: The Functional Properties and Quality of Two Novel Cassava Food Products G. Padmaja, C. Balagopalan, S. N. Moorthy, and V. P. Potty 323
vi Contents
Page
SESSION 7: INTEGRATED PROJECTS
Chapter 38 Integrated Cassava Research and Development Projects in Colombia, Ecuador, and Brazil: An Overview of CIAT’s Experiences B. Ospina, S. Poats, and G. Henry 333
39 The Cassava Flour Project in Colombia: From Opportunity Identification to Market Development Carlos F. Ostertag, L. Alonso, Rupert Best, and C. C. Wheatley 358
40 Women as Processors and Traders of Cassava Flour: The Philippine Experience D. L. S. Tan, J. R. Roa, and E. A. Gundaya 364
41 Developing the Cassava Flour Industry in Rural Areas of Indonesia A. Setyono, Sutrisno, and D. S. Damardjati380
APPENDICES
I List of Participants 393
II List of Acronyms and Abbreviations Used in Text 402
vii Contents
FOREWORD
FOREWORD
The 1994 International Meeting on who supervised the scientific Cassava Flour and Starch, held in preparation of the sessions, and Cali, Colombia, focused on cassava whose dynamism was instrumental products and their use and potential for the overall organization of the development. More than 130 event. Also much appreciated was scientists, representing 29 countries, the smoothly efficient logistical participated, presenting 45 papers support provided by Mrs. María and 80 posters, of which 41 papers Eugenia Cobo. are published in these proceedings. Not only the efficient organization, The Meeting was co-chaired by but also the number of participants, CIRAD/SAR and CIAT, and was made their diversity, the quality of their possible by the sponsorship of the presentations, and their willing EU, IDRC, MAE, NRI, ORSTOM, UBA, participation, contributed to the UNESP, and UNIVALLE. value of the discussions, making this Meeting a significant scientific Lodging and facilities were event. provided by CIAT, and we thank Dr. W. Scowcroft, Director General of CIRAD/SAR and CIAT, as Research, and CIAT employees whose co-publishers of these proceedings, efficient help was invaluable to our were assisted by CIAT’s presentations. Communications Unit. Despite careful editing and production, errors We also thank Dominique Dufour, may remain, for which we take full of CIRAD/SAR and stationed at CIAT, responsibility.
The organizers
ix Contents
PREFACE
PREFACE
Until recently, most efforts in tropical 5,000 years ago—have studies in agriculture were focused on food demand begun to emphasize increasing cereal productivity, thus the improvement of postharvest neglecting root and tuber crops such handling, processing, and marketing as cassava, long considered as a of cassava and its derived products. “primitive crop,” as “food for the Biotechnology research and poor,” and as having “poor nutritional opportunities are now also taken value.” Cassava was rarely included into account in R&D programs on in R&D programs for tropical products, byproducts, and even the agriculture. wastes produced by processing plants. But, with population increase and rapid urbanization in developing The 1994 International Meeting countries, cassava has become more on Cassava Flour and Starch, important as a source of food security organized in Cali, Colombia, and dietary calories for the demonstrated this burgeoning inhabitants of these countries. The scientific interest in cassava unusual climatic variations witnessed processing and its role in the in recent years, along with the socioeconomic growth of developing prospect of global warming, highlight countries. Producers, researchers, further advantages of this hardy, processors, and consumers of drought-resistant crop. Policy cassava products have never before makers have therefore become more met in such significant numbers to aware of the crop’s significance and share their experiences, present are encouraging its research. their work and results, and exchange information. The The root’s remarkable capacity to technological development of adapt to various agroecological cassava processing and conservation conditions and its potential for high will surely improve as participants starch yields first oriented research return to their work and apply their toward increasing productivity new knowledge. through varietal improvement, new cultural practices, and crop The themes presented during the protection. Meeting were:
Only since 1985—which is • The existing and potential uses of remarkable, considering this edible cassava in the world. root was domesticated more than
xi Cassava Flour and Starch: Progress in Research and Development
• The physical and chemical Currently, these approaches form the composition and functional only way to contribute significantly to properties of cassava flours and the socioeconomic growth of starches. developing countries. • The possibilities of bioconversion of processed products and The papers reported the most byproducts. recent results of current research • Technological improvement of programs. They also pointed toward cottage and industrial processes. future research directions and • Development of new products. suggested ways of translating results • Integrated development of into socioeconomic benefits for all cassava products to supply groups involved in cassava. market needs. With the publication of these These themes set the scene for proceedings, both those who could many stimulating discussions. The and those who could not attend the necessarily multidisciplinary Meeting will be able to reap from the scientific approach, together with wealth of knowledge presented in the participatory research these papers, and so develop new approach—both involving the methodologies and new products and various components of the cassava technology for their production, and, production, processing, and most importantly, better guide the marketing system—emerged as a direction of thinking and planning for “recurrent pattern” for quality work. their communities’ development.
Dany Griffon Rupert Best Deputy Program Director Leader, Cassava Program CIRAD/SAR CIAT
xii SESSION 1:
INTRODUCTION Adding Value to Products, Byproducts, and...
CHAPTER 1
ADDING VALUE TO PRODUCTS, BYPRODUCTS, AND WASTE PRODUCTS OF SMALL AND MEDIUM-SCALE CASSAVA-PROCESSING INDUSTRIES1
Dany Griffon*
Introduction As urbanization increases in Latin America, governments are becoming The tropical root crop cassava interested in markets for (Manihot esculenta Crantz) is cassava-derived products. National considered a ‘‘low risk’’ crop that and international research projects on adapts readily to a wide variety of cassava and its products have been agroecological conditions. It is highly set up, attracting new funding for efficient in the conversion of solar their expansion. energy to starch.
Cassava serves as a subsistence The Need for Technological crop for marginal rural populations in Research the tropics, because it efficiently uses the mineral reserves of infertile soils; it Originally focused on improved yields, can withstand climatic variations; it cultivation practices, and crop can stay in the ground unharvested protection, cassava research has, for long periods; it resists drought; since 1985, also focused on and it can function as a food-security processing, quality, and new product crop in times of famine and other development. In 1988, a 3-year disasters. European Union (EU) project, ‘‘Quality improvement of cassava-based Cassava’s importance in the fermented products,’’ involving socioeconomic development of rural French, African, and Latin American areas has gained recognition during research institutions, was set up. the last 20 years. Historically, its role This project built up knowledge and in Latin America, where the crop strengthened exchange between teams originated, was that of a basic investigating cassava conservation foodstuff for rural inhabitants. Now it and processing technologies. is also a source of income and Traditional fermented products such employment for rural populations. as ‘‘gari’’ in Togo, ‘‘chickwangue’’ in the Congo, and ‘‘sour starch’’ in Colombia were chosen for the project.
A follow-up project was proposed to the EU in 1992 as a result of interest generated by the first project, * CIRAD/SAR, Montpellier, France. especially in sour starch in Latin 1. No abstract was provided by the author. America; the need to identify new uses
3 Cassava Flour and Starch: Progress in Research and Development for cassava, and improve market together ORSTOM (France and knowledge; the need to involve small Colombia), NRI (United Kingdom), and medium-scale processing plants CIAT (Colombia), UNIVALLE in minimizing their environmental (Colombia), the University of Buenos impact by treating liquid and solid Aires (Argentina), UNESP (Brazil), and wastes; and the dynamism, CIRAD (France, Colombia, and Brazil), motivation, and experience of the whose Rural and Food Processing research groups assigned to the work. Systems Department is in charge of general coordination.2 The 3-year project was approved in November A Multidisciplinary Project 1992, and funding began in March 1993. Under the EU program ‘‘Science and technology of the living for development,’’ the EU commission Scientific Organization approved a contribution of 760,000 ECUs for a 3-year project entitled The project is structured around five ‘‘Value enhancement of products, complementary research operations, byproducts, and waste products of each coordinated by a scientist: small and medium-scale cassava-processing industries in Latin Operation 1 characterizes raw America.’’ materials and evaluates the quality of cassava flours and starches for Value enhancement involves processing. (Managed by NRI and increasing the value added during coordinated by Dr. June Rickard.) processing; designing, developing, and marketing quality products; and Operation 2 studies the treatment reducing environmental pollution of liquid and solid waste products caused by processing. from processing. (Managed by ORSTOM and coordinated by The project aims to help small- Dr. Didier Alazard.) and medium-scale cassava producers and processors strengthen their Operation 3 studies the positions in existing markets and bioconversion of flours and starches penetrate new markets. Researchers for the development of new products would study markets for cassava and for use in the food industry. (Managed its derived products; match cassava by ORSTOM and coordinated by varieties with the specific technical Dr. Maurice Raimbault.) requirements of users; improve the physicochemical, functional, and Operation 4 focuses on improving nutritional properties of cassava the functional properties of cassava flours, starches, and other products; flours and starches, and studies the develop new second-generation physicochemical and biochemical products, and carry out feasibility properties necessary for elaborating evaluations; and identify locally new products. Some of the new feasible technologies for treating waste products being studied are modified products. starches, cyclodextrins, glucose and maltose syrups, extruded products, The project has adopted a multidisciplinary—agronomy, economics, and biotechnology—and 2. For explanation of acronyms, see ‘‘List of interinstitutional approach to achieve Acronyms and Abbreviations Used in Text,’’ optimal impact. The project brings p. 402.
4 Adding Value to Products, Byproducts, and... and fat analogs. (Managed by Dr. D. Dufour in Cali, Colombia, and CIRAD/SAR and coordinated by Dr. G. Chuzel in São Paulo, Brazil.) Dr. Gerard Chuzel.)
Operation 5 studies the traditional Conclusions markets for cassava and potential markets for newly derived cassava The work plan, research teams, and products. (Managed by CIAT and financing became operative in 1993. coordinated by Dr. Guy Henry.) The first results of the research are presented in these proceedings, The wide range of cassava clones showing that added value is in the global germplasm collection indispensable in the generation of held at CIAT is vital to the project. income and employment. To obtain it, the following activities must be carried The UNIVALLE team in Colombia out: varietal improvement to satisfy and the UNESP team in Brazil are technological applications; involved in the research operations improvement in raw material mentioned above, and in forming links conservation and processing; between processors and product innovation and diversification of final users. The University of Buenos Aires products; attention to product quality; in Argentina studies the bioconversion and marketing of the final products. of flours and starches. Cassava producers, processors, Accountable to the EU, and traders can benefit from the CIRAD/SAR is responsible for the scientific and technical knowledge overall scientific and financial generated by this project, thus coordination. (Managed by obtaining a better market response Dr. D. Griffon with Dr. Nadine Zakhia. toward this long-neglected tropical In Latin America, coordinators are starchy food.
5 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 2
CORAF NETWORKS1
G. Hainnaux*
What Is CORAF? CORAF is run by a 10-man follow-up committee, six who represent The Conférence des responsables de African national programs and four recherche agronomique en Afrique de who are associate members from l’Ouest et du Centre (CORAF) is a tool European countries. This committee for cooperation in agronomic research. elects, from among its members, a It provides a framework for collective president and a vice president to action and for the exchange of represent CORAF. They are assisted information and experience. CORAF by the executive secretariat. aims to:
(1) Promote cooperation, collective Associate Networks action, and information exchange among member institutions; An associate research network is a (2) Define common research group of researchers who work objectives; together on a research theme (3) Prepare common research recognized as priority by CORAF. The projects; network aims to: (4) Create, operate, and develop associate networks and regional (1) Strengthen existing agronomic research workers’ teams; and research systems and give them (5) Collaborate with international regional and international agronomic research centers, dimension; regional or international (2) Promote the acquisition of organizations, and funding scientific knowledge and optimal agencies. use of results; (3) Encourage joint action with The institutional and operative International Agricultural Research organs of CORAF are the plenary Centers (IARCs) and with other conference, follow-up committee, international and regional executive secretariat, and associate organizations; networks. (4) Prepare projects and submit them to external funding agencies; (5) Encourage evaluation of research in various agroecological and * Cassava Network, Institut français de recherche scientifique pour le développement socioeconomic conditions; and en coopération (ORSTOM), Montpellier, (6) Facilitate the setting up of France. interdisciplinary teams, and the 1. No abstract was provided by the author. training of researchers.
6 CORAF Networks
At present, six associate The network appoints an authority networks belong to CORAF, doing to lead each project and specifies the research on groundnuts, cotton, scientific objectives, duration, maize, cassava, rice, and resistance partners, and resources to be to drought. The CORAF networks acquired. The network’s steering take into account the bilateral and committee determines the timing and multilateral relationships of methodology for the internal scientific member institutions. evaluation of the work.
Organization and operation of associate networks Base Centers
An associate network has a general A base center is an agronomic assembly, and a steering research center that belongs to a committee. The general assembly is national network and is open to composed of the coordinator, regional and international cooperation national correspondents, and one to within the framework of a network. It several associate correspondents. brings together sufficient human, The steering committee comprises financial, and material resources to the coordinator, correspondents, attain scientific objectives and achieve three members nominated by the results that are applicable or general assembly, two scientific adaptable to other countries having authorities outside the network and the same development preoccupations. nominated by the general assembly, and donor representatives. The Operation steering committee assists the coordinator in managing the A base center is placed under the network and in following up its aegis of an international network and scientific activities. of the national network that shelters it. It: The general assembly’s mission is to establish scientific priorities (1) Provides the networks with and research orientations. It liaises supplementary means for with scientific partners and with reinforcing a national program other networks, and convenes once (scientific personnel, equipment, every 3 years. operations); (2) Contributes to regional Research projects cooperation by improving the working relationships among The scientific activities of a given research workers of the same network are divided into major region (visits, workshops, themes that emerge according to seminars); national program needs. These (3) Participates in the training and themes are implemented as retraining of scientific and projects, which take into account: technical personnel of countries of the region; (1) The scientific priorities within (4) Provides expertise to third parties each theme, identified by the in the form of support or network’s general assembly; consultation; and (2) The potential of each of the (5) Promotes the diffusion of network’s partners; and information and publication of (3) Acquired experience and scientific and technical existing work. documents.
7 Cassava Flour and Starch: Progress in Research and Development
Activities International Board for Soil Research and Management (IBSRAM), based in Base center programs are planned with Bangkok, Thailand; and the the following factors taken into International Plant Genetic Resources account: national agricultural policies; Institute (IPGRI), based in Rome, Italy. development needs of each country; national research programs; priorities Major research priorities defined by the respective network; scientific capabilities of members of the The Network has three main areas respective network; and other regional of priorities: and international arrangements in member countries or outside. These (1) Make an inventory of, characterize, programs aim to: and evaluate germplasm for selection; (1) Improve crops and livestock (2) Develop technologies for promoting according to socioeconomic, longer shelf life, postharvest agronomic, biological, and handling, and improving nutritional edaphoclimatic conditions; quality; and (2) Develop living collections to make (3) Study the management of possible the sharing of available cassava-based systems to improve genetic resources among member system productivity and conditions institutions; and for propagation. (3) Establish databases and encourage joint studies of common interest. Major collaborative projects
CORAF has begun establishing thematic The Cassava Network: base centers in the Congo and Togo. An Example of an Associate Four projects are under way: Network (1) “Setting up and monitoring a Members multisite agronomic evaluation of cassava in Africa.” Located in Togo, Network members number 156 it has researchers from the Congo, researchers from agricultural research Côte d’Ivoire, France, and Togo. institutes of CORAF member (or (2) “Improving African cassava associate member) countries, that is, cultivars.” Located in the Congo, Benin, Burkina Faso, Cameroon, the researchers come from the Central African Republic, Chad, the Congo, Côte d’Ivoire, France, Italy, Congo, Côte d’Ivoire, France, Gabon, and Spain. Guinea, Madagascar, Mali, Niger, (3) “Improving detoxification methods.” Senegal, and Togo. Also located in the Congo, the researchers are from the Congo, Associate network members are France, and Togo. researchers from agricultural research (4) “Improving foodstuffs processed institutes of countries who do not from fermented cassava.” Again belong to CORAF: Belgium, Colombia, located in the Congo, the researchers Italy, Rwanda, Spain, United Kingdom, are from Belgium, Colombia, the USA, Germany, and Zaire. Congo, France, Mexico, and Togo.2
Other organizations connected with 2. For more information about the Cassava the Network are the International Network, contact the Coordinator, Dr. Joseph Mabanza, DGRST-ORSTOM, BP 181, Brazzaville, Institute of Tropical Agriculture (IITA), Congo; tel.: (242) 81 26 80 or 81 26 81; telex: based in Ibadan, Nigeria; the 5404 (Attn. ORSTOM); fax: (242) 83 22 05.
8 CORAF Networks
Summary of projects and activities carried out by the Cassava Network
Project Activity Country
(1) Improvement of production, (a) Create a base center to Cameroon, the Congo, Gabon, processing, and nutritional improve cassava varieties and Zaire transformation and quality of cropping systems cassava in Central and West Africa (b) Search and evaluate local Central Africa, Cameroon, the cultivars; set up a multisite Congo, Gabon, Guinea, Benin trial network to assess the genotype-by-environment interaction (c) Improve cassava processing Network member countries: and conservation practices; France, Germany, Spain improve nutritional quality of products and byproducts
(2) Cassava agronomy in West (a) Create a thematic base Benin, Côte d’Ivoire, France, Africa center on the improvement of Germany, Ghana, Guinea, cassava agronomy Senegal, Sierra Leone, Togo
(b) Improve management of soil Same countries as above fertility in cassava-based farming systems (c) Implement biological control Countries of the networks of cassava pests
9 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 3
THE CASSAVA BIOTECHNOLOGY NETWORK AND BIOTECHNOLOGIES FOR IMPROVING THE PROCESSING QUALITY OF CASSAVA1
A. M. Thro*, W. M. Roca**, and G. Henry***
Introduction then, many cassava biotechnology research projects have been organized Cassava plays two roles in tropical and funded (Table 1). agriculture: it provides food security for many countries; and is a source of raw material for agroindustrial CBN Objectives development. Because cassava is a highly reliable crop, even on relatively (1) Identify priorities for cassava poor soils, it can play these roles in biotechnology research. areas otherwise poor in resources. (2) Stimulate complementary, collaborative biotechnology The Cassava Biotechnology research on topics of established Network (CBN) is one response by priority through (3). CIAT to cassava’s incognito outside (3) Foster free exchange of the tropics. By 1984, powerful new information on cassava biotechnological tools for agricultural biotechnology research, including research were developing rapidly but techniques, results, and materials. chiefly in countries where cassava was not grown. Thus, little was being done to apply these new tools to cassava Defining Biotechnology even though biotechnology could significantly enhance cassava as a Among the many definitions of traditional staple and help develop biotechnology is that formulated at the new end uses for diverse markets. International Meeting on Cassava Flour and Starch (held 11-15 January, The CBN was founded in 1988 to 1994, at CIAT, Cali, Colombia): provide a forum for cassava biotechnology issues and to foster “the deliberate use of an cassava biotechnology research on organism, or part of an priority subjects (CIAT, 1989). Since organism, to make or modify products or to improve plants or animals.” * Cassava Biotechnology Network, c/o CIAT, Cali, Colombia. Biotechnologies in the context of ** Biotechnology Research Unit, CIAT, Cali, cassava processing include both Colombia. genetic manipulation and the use of *** Cassava Program, CIAT, Cali, Colombia. microorganisms to effect desired 1. No abstract was provided by the authors. changes.
10 The Cassava Biotechnology Network and...
Table 1. Cassava biotechnology research projects, partial listing, 1994.
Research area Number of Countries and projects international centersa
Tissue culture, Many Barbados, Brazil, Cameroon, Cuba, China, micropropagation Indonesia, Nigeria, Panama, Peru, Samoa, Venezuela, Zaire, and others CIAT, IITA Regeneration 9 China, France, the Netherlands, UK, USA, Zimbabwe CIAT, IITA Transformation 7 Brazil, Canada, UK, USA CIAT, IITA Molecular mapping, 6 France, UK, USA markers, fingerprinting CIAT, IITA Virus resistance 3 China, the Netherlands, USA, Zimbabwe Cyanogenesis 7 Denmark, the Netherlands, Thailand, USA CIAT, IITA Photosynthesis 2 Australia, USA Cryopreservation 2 France CIAT Processing Many Argentina, Brazil, Colombia, the Congo, France, Ghana, India, Nigeria, South Africa, Tanzania, UK, and others CIAT a. IITA = International Institute of Tropical Agriculture, based in Ibadan, Nigeria.
CBN’s Interest in Cassava consumption, and so cassava Processing, Including production, were falling in Latin Flour and Starch America; and that demand for cassava seemed to be present but the market CBN’s interest in cassava processing, was generally unable to bring cassava including flour and starch, traces to the consumer, either in fresh or back to the cassava demand studies processed form. This meant that CIAT conducted from 1984 to 1986 cassava’s advantages—high yields of (CIAT, 1987). These were extensive high-quality carbohydrate produced at studies of current and potential low cost and even on poor soils—were consumption of cassava, consumer not benefiting farmers nor urban preferences for cassava versus other consumers as they might. This staples, income generation and translated into a high priority for employment opportunities in cassava research on cassava processing and processing, and use of cassava in products to increase markets for the animal feeds. The possibilities for crop and provide consumers with expanding the cassava market were desirable products at low cost. also studied, including factors such as production costs, competing crops, The CBN conducted its own and government policies. priority assessments in 1988 (CIAT, 1989) and 1991. Its 1991 survey was The studies showed that cassava of experts on the value of different production potential exceeded cassava possible applications of biotechnology consumption; that cassava to cassava (Henry, 1991). It revealed
11 Cassava Flour and Starch: Progress in Research and Development that, among possible biotechnological from cassava users, suggests that a innovations for cassava, improving strong demand exists for research on starch quality had a high, anticipated the quality of cassava flour, even in impact on small-scale farmers and on areas with near-subsistence farming, the market value of cassava (Table 2). where such demand might not be expected. In late 1994, the CBN began a 5-year study to develop a versatile framework for using primary data for Current Research in cassava research priority setting. This Biotechnology with will refer especially to assessing the Reference to Cassava relative advantages of biotechnology Quality and Processing as against other research approaches. Genetic transformation of cassava The CBN has also begun to establish its own direct contacts with Genetic transformation, or genetic the ultimate users of cassava engineering, refers to inserting DNA of research. In 1993, a CBN case study one genetic material into a cell of was conducted in northern Tanzania another genetic material; ensuring the where the staple food is a stiff porridge DNA’s successful incorporation into of cassava flour. The flour is obtained the cell’s genome; and, if the DNA by pounding dried-then-fermented encodes one or more genes, cassava pieces. Villagers had specific subsequently expressing those genes quality preferences for the traditional in the phenotype of the cell. The most product; some women had also promising methods used to genetically experimented, but unsuccessfully, transform cassava include physically with mixing cassava and wheat flour bombarding cells with microprojectiles to produce baked goods for sale in the coated with DNA, and using the small village restaurant (wheat flour bacterial vector Agrobacterium was expensive and often scarce). tumefaciens.
CBN teams were often asked for Although single cassava cells have suggestions on improving the local been transformed, they have yet to be methods of cassava processing, or on regenerated as uniformly transformed making a greater variety of products. plantlets. Regenerating from single This perspective, gathered directly callus cells or from protoplasts—
Table 2. Relative importance of cassava constraints and opportunities for which biotechnology may have a relative research advantage, by region and by anticipated impact of biotechnological innovations on small-scale farmers and market value of cassava.a
Biotechnology Importance by region Impact of innovations research topics Africa Latin America Asia Yield Market increase advantage
Viral diseases +++ +++ + +++ + Insect pests +++ +++ + +++ + Cyanide toxicity +++ + ++ 0 ++ Starch quality ++ ++ +++ 0 +++ Postharvest root ++ +++ +++ 0 +++ deterioration a. +++ = high; ++ = medium; + = low; 0 = no change.
SOURCE: Roca et al., 1992.
12 The Cassava Biotechnology Network and... already successfully used for genetic any developmental stage, even using transformation in other species—has DNA from seedlings. not been reported for cassava. In vitro regeneration of cassava plantlets has If, for example, molecular markers been achieved through somatic were established for a certain desired embryogenesis in a wide range of cooking quality of cassava, then a genotypes. These somatic embryos breeding population could be screened arise from multicellular buds and, for that cooking quality even at the when transformed, are chimeric. seedling stage, and even if the physicochemical basis of the desired Culture studies in embryogenic cooking quality was unknown. suspension are so far promising, and the possibility of other Cassava genomic and cDNA single-cell-based regeneration systems libraries have been produced. A should be investigated. mapping progeny has been developed from the cross Nigeria 2 X ICA Mapping the cassava genome Cebucan, whose parents were selected according to their variation for both A framework genetic map of cassava, agriculturally interesting traits and based on molecular markers, is now molecular markers. The first group of under construction through useful polymorphic markers has been collaborative interchange agreements identified. When completed, the between CIAT and the U.S. framework map and the mapping Universities of Georgia and population will be made available to Washington—St. Louis. Several types cassava breeders and other of molecular markers are being used researchers. in the initial mapping work, including RFLPs from both total genomic DNA Genes for starch quality in cassava and cDNA, and RAPD primers.2 Several research groups, for example, A molecular map of markers in Brazil, the Netherlands, and CIAT, linked to traits of interest has the are interested in working on advantages that molecular markers transgenic approaches to cassava are found in all genotypes, they are starch quality and quantity. To numerous (from hundreds to produce transgenic cassava with thousands in species so far appropriate characteristics, investigated), and they are researchers need to control the phenotypically neutral. This means proportions of amylose to amylopectin that any normal plant will express so to permit new or wider uses of many of them. A further advantage, cassava starch. One form of control is and perhaps the most valuable to through genes. plant breeders, is that molecular markers are independent of external A private research group at environment or the organism’s Wageningen University, the developmental stage. As a result, Netherlands, used their work with molecular markers, and any traits potatoes to clone the starch linked with them, can be scored and biosynthetic genes of cassava: selected in any environment and at granule-bound starch synthase (GBSS, responsible for amylose synthesis), and branching enzyme
2. For explanation of acronyms, see ‘‘List of (BE, responsible for the cross linkages Acronyms and Abbreviations Used in Text,’’ that form amylopectin). This group is p. 402. also working on regenerating and
13 Cassava Flour and Starch: Progress in Research and Development genetically transforming cassava and compounds in the plant? Is there a is positioned to test the starch genes relationship between root cyanogen in cassava as soon as a content and processing quality? transformation protocol is developed. Although research on these topics has Because the research is privately increased, much more is needed. supported, the genes may not become available for public use, except in the long term. Postharvest Deterioration of Cassava CIAT (whose research results become publicly available) may be very As cassava becomes more important close to having a transformation as an industrial crop, the logistics of protocol for cassava, which, if supplying fresh cassava to processing confirmed, will then be optimized. plants becomes more critical. Cassava CIAT is also investigating the priority roots that can be stored for more than applications that are the ultimate a few days would let processors keep a objective of developing the technology. reserve of raw material and thus In accordance with cassava research operate more nearly at maximum priorities, CIAT is working with efficiency. published sequences of the BE, using polymerase chain reaction (PCR) A multidisciplinary approach has technology and a cassava genomic been outlined for addressing rapid library developed at CIAT. To date, postharvest deterioration of cassava CIAT has obtained several DNA clones, roots, a significant production and which may contain parts of the BE marketing constraint. Four years ago gene and is sequencing the clones to this problem was insufficiently verify this. Confirmed clones will be understood to be considered used to “fish out” the complete gene researchable. Now, if funds were from cassava genomic DNA. available, research on cassava postharvest deterioration would integrate biotechnology, crop Cassava Cyanogenesis improvement, and recent advances in molecular genetics. Understanding the biochemistry of cassava cyanogenesis has progressed significantly. Researchers at the Microorganism-based University of Newcastle (UK) have Biotechnologies for Cassava cloned for linamarase, a key enzyme in the cyanogenesis pathway. When a This new area of interest for CBN is transformation protocol is available, well covered by other papers in these this cloned gene can be used to proceedings (Session 4). produce acyanogenic cassava genotypes for use in research on the role of cassava cyanogens and in plant Outlook breeding. Experiences with other crops suggest Researchers must first understand that a genetic transformation protocol the implications of cyanogens for for cassava is not far off. Starch gene cassava production and use before constructs, both publicly available applying results of cassava and private, will probably be ready for biotechnology research to testing in transgenic cassava plants as cyanogenesis. For example, what is soon as a durable transformation the role of cyanogenic glucoside protocol is available, pending
14 The Cassava Biotechnology Network and... observance of all applicable biosafety Henry, G. 1991. Assessment of socioeconomic regulations. Work on the framework constraints and benefits to small-scale molecular map of cassava is in farmers from cassava biotechnology research. In: CIAT. Proposal for progress. Directoraat Generaal voor Internationale Samenwerking (DGIS), Neths., funding of coordination and References activities of the Cassava Biotechnology Network (CBN). Cali, Colombia.
CIAT. 1987. Global cassava research and Roca, W. M.; Henry, G.; Angel, F.; and Sarria, development: the cassava demand R. 1992. Biotechnology research studies and implications for the applied to cassava improvement at the strategies for the CIAT Cassava International Center for Tropical Program. CIAT Cassava Program Agriculture (CIAT). Agric. Biotech. Strategy Document prepared for the News Inf. 4:303N-308N. Board of Trustees Meeting, June, 1987. Cali, Colombia.
______. 1989. Report on the founding workshop for the Advanced Cassava Research Network, held at CIAT, Sept. 6-9, 1988. Cali, Colombia.
15 SESSION 2:
CURRENT USE AND FUTURE POTENTIAL Starch Potential in Brazil
CHAPTER 4
STARCH POTENTIAL IN BRAZIL1
M. P. Cereda*, I. C. Takitane*, G. Chuzel**, and O. Vilpoux***
Cassava Starch Production Because of its high quality and and Uses high value (US$1.50/kg), arrowroot will take a significant part of the Brazilian starch production is almost future starch market. Cassava 1 million tons per year: 76% from starch, in contrast, is a low-value maize (700,000 t/year), 23% from product, with prices ranging from cassava (220,000 t/year), and the US$0.27 to US$0.40/kg (Ademir remainder from other crops such as Zanella, 1992-1993, personal potato and rice (500 t/year) (Ademir communication). Zanella, 1992-1993, personal communication). Being traditional Annual world production Brazilian foods, the last two crops are of starch is currently about unlikely ever to play an important 29 million tons, obtained from maize role in the starch market. (12 million), wheat (10 million), potato (4 million), cassava About 45% of maize starch is (0.8 million), and others (2.2 million) used raw (320,000 t/year), 40% as (Chuzel, 1991). The main starch glucose and malto-dextrins producers are USA (maize), Canada (280,000 t/year), and 15% as (wheat), and the European Union modified starches (100,000 t/year). (potato). In contrast, about 68% of cassava starch is used raw (150,000 t/year), The USA imports 150,000 t of 18% as modified starch cassava starch, the EU 50,000 t, and (40,000 t/year), 10% as sour starch Canada 10,000 t, representing only (22,000 t/year), and about 3% as about 1% of world starch production, tapioca (8,000 t/year) (Ademir but 25% of the world’s cassava starch Zanella, 1992-1993, personal production. Japan imports another communication). 300,000 t of cassava starch (Lorenz Industry, 1990, personal communication). These countries use cassava starch to manufacture modified starches (Table 1). * Faculdade de Ciências Agronômicas (FCA), Universidade Estadual Paulista (UNESP), São Paulo, Brazil. Knight (1974) lists different ** CIRAD/SAR, stationed at UNESP/FCA. starches and their use in food *** French Technical Cooperation, stationed at (“waxy” starch has a high level of UNESP/FCA. amylopectin, a result of genetic 1. No abstract was provided by the authors. modification):
19 Cassava Flour and Starch: Progress in Research and Development
Use Starches used Function
Spice for salads Maize + “waxy” Provide stability in acidity, cutting, starch mixtures and temperature
Filling for “Waxy” starch Provides texture, transparency, fresh-fruit pies and acid stability
Filling for “Waxy” starch Provides stability in acidity and frozen frozen-fruit pies texture (does not coagulate), and transparency
Maize-type cream “Waxy” starch Provides heat stability and high viscosity
Ready-made puddings Maize + “waxy” Provide stability in temperature, frozen starch mixtures texture, and cutting
Baby foods “Waxy” starch Provides stability in frozen texture and high viscosity
Table 1. Applications (in percentage) of cassava starch in USA and the European Union.a
Crop Product Glucose Fructose Alcohol Paper Modified Raw
Maize 30 20 10 10 20 10 (40) (20) (-) (10) (20) (10)
Wheat 50 30 10 - 10 - (60) (20) (-) (10) (10) (-)
Potato - - - - 90 10 (-) (-) (-) (10) (80) (10)
Cassava - - - - 100 - (-) (-) (-) (-) (100) (-) a. Percentages in parentheses are values for the European Union.
SOURCE: Lorenz Industry, 1990, personal communication.
Brazil, the world’s leading environmental conditions and producer of cassava (Table 2), uses competition with the tobacco industry, 80% of its production in food. which has a quicker turnover of crops Although the national production of (cassava takes 1 year to mature). cassava is spread over most Brazilian states (Table 3), northern and northeastern Brazil grow 67% of the Cassava Starch Industries national crop. Most is used as and Markets food—of the 1991 crop, only 4% was transformed into starch. Cassava starch industries are located in Santa Catarina, Paraná (78%), São Table 4 compares cassava Paulo, Minas Gerais, and Mato Grosso production in Paraná state with that do Sul (Table 5) with 56 industries in Santa Catarina: planting area in registered with the Associação the first increased by 64%, as did Brasileira dos Produtores de Amido de production (65%), in the last 10 years. Mandioca (ABAM, 1992-1993). But In contrast, in Santa Catarina, the founding of many new industries planting area dropped by 35%, as did may have increased this number to 70. production (-13%), because of Processing capacity is variable, for
20 Starch Potential in Brazil example, the average is 221 t/day in expansion of cassava starch use. The Paraná state and 109 t/day in Santa structure of the maize starch market Catarina. These industries have in Brazil is oligopolistic and is formed equipment of international standard. by three multinational enterprises: National Starch, Cargil, and Corn The Centro Raizes Tropicais Products Corporation. (CERAT), Universidade Estadual Paulista (UNESP), researched 12 Maize and cassava starches are cassava flour industries in Santa commercialized in the same markets: Catarina in 1993 through interviews, foodstuffs (cheese breads, cookies, which showed an overall production of ice-creams, chocolates, processed 10,450 t. These results, however, meat, and forcemeats), paper and differed from ABAM’s data of the same cardboard, textiles, pharmaceutical year (16,750 t). products, glues and adhesives, and modified starches. Cassava starch production faces strong competition from maize starch, The biggest problem facing the the prices of which are stable, and cassava starch industry is a price quality is high and consistent. Such variability that ranges between 60% competition inhibits the growth and and 70%. Prices for cassava roots
Table 2. World production of cassava roots (in millions of tons). Numbers are rounded.a
Producer 1961-1965b 1969-1971b 1991c
Major producers 50.0 (67) 63.5 (66) 99.4 (65) Brazil 21.9 (29) 29.9 (31) 24.6 (16) Thailand 1.7 (2) 3.2 (3) 20.3 (13) Nigeria 7.2 (10) 9.4 (10) 20.0 (13) Zaire 7.7 (10) 10.2 (11) 18.2 (12) Indonesia 11.8 (16) 10.6 (11) 16.3 (11)
Otherd 24.5 (33) 33.2 (34) - -
Total 75.0 (100) 96.7 (100) 153.7 (100) a. Values in parentheses signify proportion of total by percentage. b. Compiled from FAO, 1990. c. CIAT, 1993. d. About 75 countries.
Table 3. Brazilian cassava production, 1991 crop, by region.
Region Area Output Proportion of Average (ha) (t) national crop yield (%)a (t/ha)
North 328,792 4,461,354 18 13.5 Northeast 1,132,889 12,005,948 49 10.5 Middle west 68,819 1,082,950 5 15.7 Southeast 134,775 2,118,052 9 15.7 South 277,835 4,862,480 19 17.5 Total 1,943,110 24,530,784 100 - a. Numbers are rounded.
SOURCE: IBGE and CEPAGRO, 1992.
21 Cassava Flour and Starch: Progress in Research and Development
Catarina
22.1 17.3
21.4 17.1
19.6 18.1
21.0 18.0
21.7 16.1
20.0 14.4
20.8 17.2
20.0 13.3
21.7 16.7
19.5
19.7 19.3
Catarina
Average yield = 18.9 16.5
86 -13
52 -1
52 3
79 -2
65 -13
72 -13
39 4
33 9
41 100
13 19
100
Catarina
2.1 1.1
2.1 1.0
1.8 1.1
1.8 1.2
1.6 1.2
1.7 1.1 1.7 1.2
2.2 1.0
2.0 1.0
1.2
1.3 1.4
Catarina
36 -21
12 20
63 -24
60 -36
37 -4
37 100
37 -14
25 -15
64 -28
119 -35
100
Catarina
Paraná Santa Paraná Santa Paraná Santa Paraná Santa Paraná Santa
62,490
85,800 84,812
69,870 74,688 85,800 88,443
85,445 75,738 85,242 69,469 77,839 74,756
101,854 67,596
100,000 56,873
102,265 63,370
137,000 57,379
crop (ha) (%) (millions of tons) (%) (t/ha)
Year of Area Growth rate Production Growth rate Yield
1986/87 1987/88 1988/89 1989/90 1990/91 1991/92 1992/93
1981/82 1982/83 1983/84 1984/85 1985/86
Table 4. Cassava production in the states of Paraná and Santa Catarina, Brazil, 1981-1993. Numbers are rounded.
SOURCE: IBGE, various years.
22 Starch Potential in Brazil
Table 5. Brazilian starch production (in tons) for 1993, and estimated for 1994.
State Starch industries Production Estimated (no.) 1993 production 1994
Paraná 23 132,900 189,600 Santa Catarina 21 31,550 56,600 São Paulo 5 15,500 28,600 Mato Grosso do Sul 4 23,000 29,300 Mato Grosso 2 1,500 5,100 Espírito Santo 1 3,000 5,000 Total 56 207,450 314,200
SOURCE: ABAM, 1993. varied erratically between US$19.50 of cassava starch (f.o.b. at factory) are (1983), $33.50 (1992), and $51.00 more stable than those of cassava (1989) per ton during 1980-1992 roots, which are vulnerable to the (Ademir Zanella, 1992-1993, personal roots’ perishability and fluctuate with communication). root production. Products using cassava and maize starches are elastic, Other problems include the fact that is, income positive, whereas that the Brazilian cassava starch products from cassava flour are industries must also stop working inelastic. for 4½ months/year. Low root production, a long vegetative cycle, and an inferior quality starch also make 13,500 cassava starch production costly, 11,500 compared with that of maize starch. In 9,500 the last 3 years, maize prices have 7,500 fallen against those of cassava roots, CR$/t 5,500 thus making the prices of maize starch 3,500 more competitive and maize starch 1,500 more available, and thus more used by 1980 82 84 86 88 90 92 industries (Venturini Filho, 1993). Year
Figure 1. Cassava farmgate prices, Paraná state, Large Brazilian agroindustrial Brazil. Correct prices until August complexes that use starch as a raw 1993 by general price index-internal material have invested in this area to demand (deflator). (After Fundação guarantee an adequate supply of good Getulio Vargas, 1993, personal communication.) quality and suitably stored starch. Three examples can be cited: National 6,000 Starch in Santa Catarina and Nestlé in 5,000 Paraná have just bought their own 4,000 cassava starch industries. Fleischman 3,000 Royal in São Paulo has used its own 2,000 factory, Júpiter, to manufacture its CR$/50 kg 1,000 own cassava starch for more than 0 5 years. 1980 82 84 86 88 90 92 Year Figures 1, 2, and 3 show differences between the real prices of Figure 2. Real wholesale prices for cassava flour. Correct prices until August and raw material (root), cassava flour, and September 1993 (after readjustment for raw cassava starch in Paraná. Prices inflation). (After ABAM, 1993.)
23 Cassava Flour and Starch: Progress in Research and Development
200 Acknowledgments 150 We thank Ademir Zanella of Halotek 100 Fadel Industrial Ltd. for the data used CR$/kg 50 in the tables.
0 1986 87 88 89 90 91 92 93 Year References
Figure 3. Real prices of raw cassava starch, ABAM (Associação Brasileira dos Produtores industrial f.o.b., Paraná, Brazil. Correct de Amido de Mandioca). 1992-1993. prices until August 1993 by general Produção; estoques, capacidade price index-internal demand and in industrial das fecularias brasileiras. September 1993 after readjustment for inflation. (After ABAM, 1993.) Paranavaí, Paraná, Brazil. Chuzel, G. 1991. Cassava starch: current and potential use in Latin Although all Brazilian states America. Cassava Newsl. 15(1):9-11. produce cassava, only the states of the CIAT. 1993. Cassava: the latest facts about an south (Santa Catarina and Paraná), ancient crop. Cali, Colombia. southeast (São Paulo), and middle (Pamphlet.) west (Mato Grosso do Sul) are technologically prepared to produce FAO (Food and Agriculture Organization of the cassava starch. United Nations). 1990. Yearbook. Rome, Italy.
Other constraints to expanding the IBGE (Instituto Brasileiro de Geografia e cassava starch market include Estatística). 1981-1993. Censo farmers’ ignorance of the market, and agropecuário. Fundação Instituto lack of promotion of the virtues of Brasileiro de Geografia e Estatística (FIBGE), Rio de Janeiro, RJ, Brazil. cassava starch. Promotional pamphlets could be created by the ______and CEPAGRO (Centro Estadual de CIRAD/SAR-UNESP project to target Pesquisa Agronómica). 1992. specific markets, potential markets, or Levantamento sistemático da growing existing markets. produção agrícola. Fundação Instituto Brasileiro de Geografia e Estatística (FIBGE), Rio de Janeiro, RJ, Brazil. An example of a growing market p. 46-47. for cassava starch is beer manufacture (Venturini Filho, 1993). To make Knight, J. W. 1974. Specialty food starches. 7,400 g of beer, 474 g of cassava In: Cassava processing and storage: proceedings of an interdisciplinary starch are needed. Brazilian beer workshop. Pattaya, Thailand. p. 77-87. production is 5.8 billion liters. Current mixes use malt with maize Venturini Filho, W. G. 1993. Fécula de and rice grits. If the grits market mandioca como adjunto de malte na could be divided into three to include fabricação de cerveja. Ph.D dissertation. Faculdade de Ciências cassava starch, a potential Agronômicas, Universidade Estadual 120,000 t of cassava starch would be Paulista (UNESP), Botucatu, SP, needed for this sector alone. Brazil. 234 p.
24 Producing Cassava Flour in Peru and...
CHAPTER 5
PRODUCING CASSAVA FLOUR IN PERU AND ITS PROSPECTS FOR DEVELOPMENT1
S. Salas Domínguez, Y. Guzmán, and S. Aquino*
Introduction Peruvian Amazon and the humid tropics. The Instituto de Concern is increasing worldwide about Investigaciones de la Amazonía the social problems of poverty, Peruana (IIAP) established a pilot unemployment, hunger, and mounting plant for producing cassava flour in child mortality. In Peru, preliminary Pucallpa, capital of the Department of data from the most recent census Ucayali, in the center of the Peruvian shows that a population explosion has Amazon. This flour is used for human taken place in the last few years. This consumption and as a substitute for factor, together with Peru’s inputs used in plywood and sociopolitical and economic problems, bread-making industries. has depressed living standards, especially in rural areas, which has to produce enough food to feed nine city Cassava Production in dwellers for every rural inhabitant. Ucayali, Peru But subsistence agriculture is prevalent because of agroecological In 1991, national cassava production constraints, lack of infrastructure, was 405,725 t, twice that of the and lack of technical and economic 1950s. In contrast, other staples such resources. as potatoes, wheat, and quinoa (Chenopodium quinoa) have decreased More than two-thirds of Peru has by one-third. Ucayali produces agroclimatic conditions suitable for 20,000 t of cassava annually, fourth tropical crops that can grow in poor in national production. Consumption soils, with little fertilization, and are centers are located on different resistant to disease. Such crops have tributaries of the Ucayali River and, been rapidly distributed, and are the although tributaries are navigable, most valuable resource in fighting most cassava is wasted because hunger and the greatest hope for rural distances are long, and boats slow and development through agroindustry. Of small. The highly perishable and these crops, cassava and plantain are bulky roots therefore do not reach the most important, both in the markets in time.
Yields in the Departments of Loreto and Ucayali vary from 10 to * Instituto de Investigaciones de la Amazonía 35 t/ha. The little produce that does Peruana (IIAP), Pucallpa, Peru. reach urban markets has increased its 1. No abstract was provided by the authors. price by 200% in relation to farmgate
25 Cassava Flour and Starch: Progress in Research and Development prices. In rural areas, cassava is production areas, which occurred as a traditionally processed into products result of the 1991 political and such as fariña and tapioca, but economic emergencies. because of inferior quality, these products are not sufficiently The pilot plant was conceived as competitive for urban markets. part of an integrated system. Activities were to complement each In the past, plants for producing other so to increase potential and thus cassava flour were installed in use more effectively available Pucallpa and Iquitos (Department of resources. The plant was to serve an Loreto, north of Ucayali). These failed area that suffers multiple problems, mainly because the technology did not and the Peruvian Amazon was accord with the geographical and targeted. socioeconomic conditions of the respective areas. The plant was complemented by vermiculture (farming of worms), The inhabitants of Ucayali eat agroforestry, fish farms. These sufficient carbohydrates to comply activities not only provide a market for with the minimum nutritional cassava products, but also help slow requirements set by the National down the degradation of natural Nutritional Institute. That is, resources, for example, worm humus 142,350 t of roots and tubers and helps improve poor soils. The raising 98,550 t of cereals (mostly imported of small animals, based on products wheat flour) are consumed yearly. and byproducts of rural agroindustry (such as cassava flour), helps resolve the lack of protein in the regional diet. The IIAP Cassava Flour Plant Efficient farm management (and thus higher productivity) reduces Background emigration.
The farmers of Ucayali, especially Objectives cassava producers, confront severe socioeconomic and political pressures Through research, the plant was to that often force them to emigrate en generate and adapt technologies for masse to cities or cocaine areas. In an processing flour, and evaluate and attempt to keep people on the land, establish production and quality the IIAP looked for ways to propose parameters. The plant, however, had and generate appropriate technologies, to be a successful enterprise to employment, and organization. The interest farmers in the potential IIAP suggested integrating production socioeconomic benefits of cassava systems to permit a more efficient and flour production. Once farmers began effective use of small-farm resources participating, the plant was to offer and thus improve production. training to cassava farmers and processors interested in integrating In 1989, the IIAP, with production, processing, and collaboration from CIAT (based in marketing. Colombia), began developing technology and machine prototypes for To fulfill its functions of cassava processing. A plant was technological research, flour established at “Fundo Villarica,” IIAP’s production, product promotion, and experiment station at Pucallpa, training, the plant had the following despite a recession in almost all objectives:
26 Producing Cassava Flour in Peru and...
(1) To validate, adapt, and generate management, and so sign agreements technologies for processing that permit mutual collaboration. cassava and its products. Supplies of raw material came from (2) To open markets for cassava- some sectors of the Campo Verde based products such as flour, district, near Pucallpa. flakes, and grains. (3) To integrate the use of the entire Plant operation cassava plant in animal feed. (4) To increase the value of cassava The plant operated at 60% capacity, in roots, which are underused accordance with the goal set. The because of their perishability. following five cultivars were used: (5) To gradually substitute imported Señorita, Huangana, Huanuqueña, wheat flour. Arponcillo, and Nusharuna. Best (6) To provide technical and results have been obtained with cv. organizational training for farmers Señorita with a yield of 3.2:1 (root to and mid-level technicians. flour), but is more perishable than (7) To encourage farmers to not only other roots (lasts 2 days). Cultivar produce cassava, but also to Nusharuna has the most durable process and market it. roots but its yields are low, 3.9:1, and the flour is darker because the peel is Plant facilities difficult to remove.
The plant had four sections: The percentage of loss from root (1) reception, storage, and defects after selection and preparation preparation; (2) washing; was high (15%). Although this (3) chipping; and (4) preliminary problem could be overcome by sun-drying, artificial drying, milling, differentiating root prices, farmers had and storing the final product. The to be taught the need for selection. area for storing and preparing raw material was built on higher terrain Overall, the equipment performed than was the chipping area to make well, except for the screen and dryer. use of gravity in transferring raw The minimum drying time achieved material. The dryer was a tray was 12 hours, including preliminary system used by CIAT, with a burner sun-drying. Raw material accounted that, for fuel, used wood discarded for 85% of production costs, fuel 7%, from sawmills. and labor 3%. Packaging, depreciation, and maintenance To reduce drying time, flakes accounted for the remaining 5%. destined for animal feed were first dried in trays, and then sun-dried. Marketing The basic machinery was brought from Colombia, but accessories and The plant targeted the local market, other equipment were built locally and with some initial promotion in Iquitos elsewhere in Peru. The total and Lima. Currently, demand is 70 t investment was US$27,000, including of flour per month, of which only 16 t buildings, machinery, and other could be supplied. About 60% of equipment. production is sold to bakeries (which substitute as much as 20% of wheat From the start, the IIAP flour) through the Programa Nacional encouraged the organized de Alimentación (PRONAA) and to the participation of cassava growers so private company, Cotrip, that makes they could evaluate the possibilities of water biscuits. About 20% goes to other plants under similar direct plywood industries, 5% to Lima, and
27 Cassava Flour and Starch: Progress in Research and Development another 5% to Iquitos. The bran, making bread and pasta are being together with discarded roots, is used installed to promote the establishment for animal feed. of similar projects in different rural sectors. Key market segments at a national level are still to be identified, and Training competition from imported wheat flour has to be resolved. Ucayali, for Training focuses on three levels: example, uses 700 t/month, of which (1) university theses; (2) training rural 80% is for bread making and 20% for dwellers to become qualified workers, plywood industries. or, through modular training courses, knowledgeable on any phase of the Research process; and (3) courses for the public, such as bread making for commercial The plant lacked laboratory equipment bread makers and housewives. for quality control, which was done by several universities and Achievements nongovernmental organizations (NGOs). Proximal and microbiological After 2 years of operation, the plant analyses were carried out. successfully:
At first, because water quality was (1) Identified, analyzed, and inferior and vermiculture was located improved native technology. near the plant, microbiological quality (2) Built the production was poor. Scientists found fungi, infrastructure, using locally yeasts, fecal coliforms, and available resources. Machines clostridium sulfite reducers in and equipment were simple, quantities above permissible levels, versatile, and adaptable to but no Escherichia coli nor salmonella. processing other products, such These problems have been identified as plantains, “sachapapa” or and solved, and the flour is now taro, and cassava. acceptable for human consumption. (3) Produced flour that was US$0.25 cheaper than wheat flour. Dry matter content of cv. Señorita (4) Found favorable local and is 34%. On the average, whole regional markets. These were cassava flour contains 84.2% starch, vermiculture, agroforestry, 1.4% protein, and 3.1% fiber. raising of small animals, horticulture, and pisciculture. Based on experiences in bread (5) Made the new technology making, trials were conducted with economic for small-scale farmers bakeries to establish the following to invest and rapidly recuperate formula for bread preparation: their investments, thus diminishing risks when conditions become unfavorable. Wheat flour 80 parts Yeast 3 parts (6) Established a modular system for Cassava flour 20 parts Additive 1 part installation and operation, thus Sugar 6 parts Salt 1 part enabling each phase of the process to be totally independent Fat 6 parts Water 30 parts and thus more efficient. (7) “Passed the test” of adverse Color still has to be improved but political and economic conditions, flavor and consistency are good. including violence, recession, and Currently, artisanal modules for generalized poverty.
28 Producing Cassava Flour in Peru and...
Prospectives at Tocache is being installed, with CIAT’s assistance. With collaboration An agreement has been signed with from Caritas Peru, four plants will be the Alto Huallaga Special Project to established in Puerto Maldonado introduce integrated production (southeast Peru), Iquitos and systems as an alternative to Yurimaguas (Department of Loreto), cultivating coca. Currently, the plant and Tumbes (north coast).
29 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 6
CASSAVA STARCH IN NORTHERN CAUCA, COLOMBIA: SOCIOECONOMIC EVALUATION OF ITS PRODUCTION AND COMMERCE1
Liliana Mosquera P.*, Myriam Patricia Chacón P.**, G. Henry**, and G. Chuzel***
Introduction The study is part of a research and development (R&D) program on cassava Cassava plays a major role in starch production being conducted by subsistence farming in northern CIAT’s Cassava Utilization Section. Cauca, Colombia. About 90% of root The program’s objective is to offer production is used for extracting sour technological alternatives to small-scale, starch, and as much as 80% of sour cassava starch producers. The program starch production is used for making first began in 1989, and is based on an the breads “pandebono” and informal network comprising various “pandeyuca.” Sour starch has its own Latin American laboratories and characteristic functional properties, institutions involved with cassava flavor, and aroma. starch production. The program also comprises regional working groups In northern Cauca, cassava starch that evaluate technology for starch extraction is mainly an artisanal production, study the technical and activity, although processing plants economic system, characterize and are mechanized to some extent. In evaluate products, treat waste waters, importance, this agroindustry ranks and conduct basic research on third after the sugar, and editorial and fermentation and raw material (Chuzel, publishing industries. 1991).
Our study aimed to better understand the different problems Objectives of the Study affecting cassava starch production in the region, and help researchers The general objective was to identify priority needs for possible characterize starch production and technology intervention. commerce in northern Cauca, Colombia, and so assess the technical and economic performance of small-scale, cassava starch factories. * Cassava Economics Section, CIAT, Cali, Colombia. Specific objectives were: ** Cassava Program, CIAT, Cali, Colombia. *** CIRAD/SAR, stationed at the Faculdade de Ciências Agronômicas (FCA), Universidade (1) To statistically analyze the surveys Estadual Paulista (UNESP), São Paulo, carried out by the Cassava Brazil. Utilization Section in 1990 on the 1. No abstract was provided by the authors. technical performance of
30 Cassava Starch in Northern Cauca, Colombia:...
small-scale, starch factories, and to specific sample was established. The study the economic performance of survey was therefore based on a list these and their social implications. of 35 middlemen identified in the The economic survey of starch previous survey on small-scale, factories carried out by university cassava starch producers; of these students was used as a base. 35 middlemen, 20 were surveyed. (2) To characterize the production process of cassava processing Numerous problems arose in plants and determine the capacity obtaining comprehensive information, of installed plants. especially that on the volume of starch (3) To identify the seasons when purchases and sales. Because supplies of cassava sour starch are middlemen were so reluctant to share abundant or limited and determine information on how they managed distribution channels. their businesses, a case study was (4) To analyze social characteristics conducted, based on information related to starch production and supplied by the COAPRACAUCA commerce. Cooperative, Santander de Quilichao. (5) To identify factors limiting starch production and commerce. Starch Processing and Commerce Methodology Root production is a key aspect in the The study began by surveying processing and commerce of cassava small-scale, sour-starch producers and starch in northern Cauca. Although middlemen. The target population roots are used more to obtain starch consisted of 99 small-scale starch than for human consumption, when factories, first surveyed in 1990 when market prices drop below the average the R&D project began, in the towns of Col$32/kg (US$0.05/kg), then fresh Santander de Quilichao (86 factories) cassava is sold to cassava drying and Caldono (13). Of this group, plants for use in animal feed. 35 processing plants were selected and, for reasons of efficiency, In the Cauca Department, stratified according to plant size 6,290 ha were planted to cassava in (small = fewer than 3 workers; 1991, producing 71,624 t at a yield large = 4 or more), age of equipment of 11,387 kg/ha (Departamento (new = purchased in the last 15 years; Administrativo Nacional de Estadística, old = more than 15 years old), and Colombia, 1992, unpublished data). geographic area (municipality of Santander de Quilichao or Caldono). The municipalities of Buenos Aires, Santander de Quilichao, and Caldono Selection was randomized, but planted 4,080 ha of cassava, proportional to stratum size. The accounting for 64% of the total area Stratified Sampling of Elements under cassava cultivation in Cauca. technique (Pardo Camacho, 1991; de Production reached 39,000 t, 54% of Servín and Servín Andrade, 1978), the department’s total production. which gives proportional allotment, Yields were 9.5 t/ha, almost 16% was used for sampling. below the departmental average of 11.3 t/ha. But only 2.3% of the Cassava starch middlemen were national crop (173,999 ha) is planted surveyed in Caldono, Santander de in Cauca because the root’s Quilichao, and Cali. Because no perishability, and its low and census of middlemen existed, no fluctuating prices, among other factors.
31 Cassava Flour and Starch: Progress in Research and Development
The amount of cassava on offer to The decrease in sour-starch small-scale, starch factories averages production in 1991 was caused partly 556 t/year, for a consumption of by a lack of both raw material and 456 t/year at Col$32,000/t working capital. At the same time, the (US$47.00). Although shortages of raw Colombian Government began material occur in Cauca at certain implementing a policy of “open times of the year, the annual supply of economy.” Bank credits were closed to cassava often exceeds demand, stabilize inflation at 22%. From especially for 18 of the factories in August 1990 to September 1991, the Santander de Quilichao. Located close 33 starch factories under study to the Pan-American Highway, they processed 16,878 t of starch, tend to be oversupplied. producing 3,207 t of sour starch, 1,333 t of bran, and 270 t of “mancha.” Plant production during That is, every 100 kg of roots yielded 1990-1991 was irregular: some plants 19% starch, 8% bran, 1.7% “mancha,” operated sporadically, according to the and 71.3% of both water (which availability of raw material and comprises 65% of roots) and waste, working capital. For 1990, the average that is, peel and starch lost to minimum production was 4.3 t of inefficient processing techniques. Yield starch per week and the maximum was differences among factories are caused 175.0 t. by, for example, cassava variety, harvest age, and postharvest For 1991, the plants had an handling. average production of 420 t of starch per year (8.7 t/week) and a maximum Producers can obtain as much as of 775 t/year (16.1 t/week). Such 27% starch (wet basis) with 60% figures indicate that the plants do not technological efficiency, according to work at full capacity because of the experiments by the Corporación para lack of raw material in the area. Estudios Interdisciplinarios y Asesorías Production recession caused by lack of Técnicas (CETEC), a Colombian raw material can last from 2 to organization that provides technical 12 weeks. Of the processors, 51% assistance to starch-producing farmers. stated that they required a constant Once the product is processed to 12% amount of raw material. moisture content, these values can be obtained per 100 t of cassava. For small-scale, starch factories in Yield northern Cauca, the cassava-to-starch conversion ratio is 5:1. The In 1991, sour-starch production per 200 small-scale, starch factories of this factory decreased considerably, region therefore produced a total of averaging 97 t/year. Byproducts were 8,500 t of sour starch in 1994. bran (fiber and peel left over from sieving starch) at 42 t/year and In Ecuador, the cassava-to-starch “mancha” (scum skimmed off surface conversion ratio is 5-10:1. This ratio of sedimented starch) at 8 t/year. varies greatly according to the time of Most small-scale, starch factories carry year and cassava varieties used. out sweet-starch extraction on request, Byproducts (bran and “mancha”) are but production is sporadic because sold for animal feed (Chuzel, 1991). starch quality does not always reach industrial technical specifications. In Minas Gerais, Brazil, the But, at the time of the survey, only one “polvilho azedo,” or sour starch, factory was producing sweet starch enterprises can process from 1 to 40 t (1.2 t/week). of cassava roots per day. Annual
32 Cassava Starch in Northern Cauca, Colombia:... production ranges from 20 to to surveys carried out in 1990 by 1,000 t/year, and yields from 200 to CIAT’s Cassava Utilization Section. 300 kg of starch per t of roots From August 1989 to August 1990, (Oliver Vilpoux, 1992, personal the total area planted to cassava by communication). processors averaged 106 ha, of which 43% corresponded to the processors’ own plots and 57% to rented plots. Procedures, Equipment, and For 1991, the percentage of processors Maintenance renting land for cassava cultivation decreased to 54%. That same year, In Colombia, small, semicommercial, the total area planted to cassava by cassava starch factories are called the 99 starch processors averaged “rallanderías.” These factories typically 80 ha. Thus, in the two have a grater-sieve and washer-peeler, municipalities, the 26 ha planted to both motor-driven. Their processing cassava the previous year were capacity ranges between 4.4 and 44 t destined for other purposes. of roots per week, with an overall Furthermore, of the 51% growing average of 16.2 t/week. Figure 1 cassava, only 33% owned the land and demonstrates processing in a 18% rented it; 48% lack land title medium-sized, starch extraction deeds, which reduced access to credit. factory, beginning with the acquisition The cost of leasing 1 ha ranges of roots. between Col$3,000 and Col$40,000 (US$4.43-$59.00) per month, Root supplies. Small-scale starch averaging Col$10,333.00 (US$15.34) processors do plant cassava, according per small-scale, starch factory.
Roots
Water Washing Water, external cortex, dirt
Grating
Sieving Bran
Starch
Sedimentation “Mancha” + Waste waters Moist starch Drying Fermentation Dehydration Animal feed Dehydration Drying
Drying
Sour Sweet starch
Figure 1. Processes performed in a medium-sized, cassava-starch extraction factory, northern Cauca, Colombia. (Modified after Chuzel, 1991.)
33 Cassava Flour and Starch: Progress in Research and Development
Washing and peeling. These are Drying. Starch is usually done either manually or in a rotating sun-dried on trays or terraces, or on drum. Of the survey respondents, 93% concrete floors previously covered with have mechanized these operations, plastic to prevent farmyard thus reducing women’s participation in contamination. The dried starch is processing. Before, women were then packed for market distribution. employed to peel the roots.
Grating. Grating is carried out by Commerce rotors with perforated laminae that are changed periodically. About 36% of The typical distribution of cassava factories change the laminae every sour starch begins with the cassava 90 days, 23% every 60 days, 21% every farmer who sells the roots either to 30 days, and the rest more than middlemen or directly to the starch 90 days. processor. Only 7% of processors surveyed purchase roots only through Sieving. The starch dissolved in middlemen; 65% buy directly from the water is separated from the pulp or farmer, and 28% from both. Starch is bran, which is later used in animal also distributed through middlemen or feed. Different types of fabric, placed directly to users. The middleman sells on rotating screens, are used for to the wholesaler or retailer who, in sieving, the most common being nylon turn, distributes to intermediate (58%), canvas (28%), and silk (3%). consumers such as bakeries and The fabrics are changed frequently: industries that, in their turn, 77% of processors change them every distribute their products directly to 30 days, 11% every 60 days, and the consumers or to distributors of rest after 90 days. For 89% of the processed food products (Figure 2). plants surveyed, sieves are less than 10 years old.
Sedimentation. The slurry from Cassava farmers sieving is left to settle. Particles of fiber and other fine materials that had Middlemen not been removed during sieving are separated to form “mancha,” another Starch processors byproduct used in animal feed. Sedimentation is carried out in concrete tanks veneered with wood or Middlemen glazed tile. On the average, processing plants have five sedimentation tanks, each with an average capacity to hold Wholesalers Retailers 551 kg/day. Intermediate processors Fermentation. To obtain sour (bakeries and industries) starch, the moist starch is passed through a series of tanks, where it Distributors remains 15 to 20 days until the of finished desired acidity is reached. The average products factory has five fermentation tanks, each with a capacity of 1,030 kg. Ultimate consumers Sweet starch is obtained by dehydrating and sun-drying the moist Figure 2. Typical distribution chain for cassava starch after sedimentation. starch in northern Cauca, Colombia.
34 Cassava Starch in Northern Cauca, Colombia:...
Starch processors sell most of The municipality of Santander de their products in cash but may sell on Quilichao has the highest number of credit to regular clients. These clients middlemen—which explains why 42% also pay the processor in advance of starch processors sell their product when they urgently need starch and there—followed by Caldono and Cali, the processor does not have enough each with 15%, and the other cities working capital to fulfill the demand. with 28%. For 1991, the average price A credit period is usually 19 days. per kg of sour starch was Col$230 Although commercializing products is (US$0.39). The byproducts (bran and difficult, stocks rotate quickly. Sour “mancha”) are usually sold on the starch is stored for an average of retail market in Santander de 10 days, sweet starch 8 days, bran Quilichao, being mainly used for 11 days, and “mancha” 14 days. animal feed (Figure 3).
Processors also distribute sour starch through the COAPRACAUCA Economic Evaluation of Cooperative, which groups about Small-scale, Starch Factories 30 small-scale, starch processors of the region, and through middlemen. Table 1 shows the costs involved The cooperative and intermediate in producing sour starch. All middlemen, in turn, sell the starch to small-scale, starch factories are wholesalers and retailers who then mechanized to a certain extent so distribute the product to major electricity is necessary. An average markets in the cities of Santander de factory pays US$220/year for Quilichao, Cali, Buga, Cartago, Tuluá, electricity, accounting for 1% of total Pereira, Ibagué, Medellín, Bogotá, costs. Because the factories must Cartagena, and Montería. periodically change some of
Starch processors
Middlemen
Intermediate Cooperative middlemen
Wholesalers and retailers Wholesalers and retailers
Cali Bogotá Armenia Ibagué Cali Medellín Cartago Ibagué 25% 24% 6% 6% 20% 37% 20% 8%
Medellín Pereira S/der de Quil. Pereira Palmira S/der de Quil. 7% 17% 7% 8% 6% 1%
Other cities 8%
Figure 3. Market channels of cassava starch in northern Cauca, Colombia. (From interviews with COAPRACAUCA Cooperative members.)
35 Cassava Flour and Starch: Progress in Research and Development
Table 1. Annual average costs involved in producing cassava starch (1991), northern Cauca, Colombia.
Item Col$ US$ Percentage of (1991 value) total costs
Fixed costs 2,882,000 4,836 12.1 Energy 131,000 220 0.5 Maintenance 487,000 817 2.0 Rent 1,082,000 1,815 4.6 Administration 855,000 1,435 3.6 Others 327,000 549 1.4
Variable costs 20,632,000 34,618 87.9 Raw material 16,708,000 28,034 71.5 Labor 1,751,000 2,938 7.4 Transport 1,958,000 3,285 8.0 Packing 215,000 361 1.0
Total costs 23,514,000 39,454 100.0
the equipment they incur and, even though some starch maintenance costs equivalent to 2% processors feel that this represents of total costs. an extra cost, it would guarantee more efficient operation. Small-scale, starch producers save money when they own the Of the 99 small-scale, starch factory rather than rent its premises factories operating during the study, (CIMMYT, 1993). Rental costs three had administrative costs that depend on the factory’s location in exceeded labor costs. In most cases, the region, but these are normally labor costs were notably greater than low, with little tendency to increase. administrative costs, indicating that Only two of the starch processors a balance does not exist between surveyed had explicit rental costs, these two that would ensure a accounting for 5% of total costs. distribution of the economic benefits of small-scale, starch factories. Administrative costs account for 4% of total costs. Usually, the owner The cost of buying and himself manages the factory, this transporting raw material account being his means of support. An for 71% of operating costs. Several undetermined amount of the earnings small-scale, starch factories are from the sale of starch is used for located where it is easy to purchase household expenses, that is, as his large volumes of low-quality cassava, salary. This fact, perhaps, most especially in flat areas, thus reducing influences the efficient operation of the average purchase price per kg of the factory. raw material. In 1991, average freight charges were Col$1,958,000 Administrative costs are closely (US$3,285), accounting for 8% of related to the efficiency of any total costs and exceeding enterprise. A small-scale, cassava administrative and labor costs. starch factory should have a dedicated manager with sufficient Labor accounts for 7% of total expertise to administer the factory costs. Labor is inexpensive, and during production time. The small-scale, cassava starch factories manager should be assigned a salary provide a significant source of
36 Cassava Starch in Northern Cauca, Colombia:... employment. In several rural Processing Constraints communities of the region, these factories are the rural population’s Major constraints found in cassava only source of income. Labor is also starch processing are: seasonal, being scarce during coffee harvest. Most factories’ busiest time Irregular cassava supply. A is during cassava harvest. major constraint is irregular cassava supply (Table 2), which is caused by inconstant cassava production, which Income Generated by Sour itself is related to unstable cassava Starch Sales prices. As cassava prices rise, farmers intensify cultivation, thus increasing Processors sell everything they supply and lowering prices. produce, with sour starch bringing Processors do not control the flow of the highest yearly income of raw material required to initiate the Col$22,942,000 (US$38,493) or 89% process; if they did, they could plan of the total income. Byproducts production according to the market brought Col$2,909,000 (US$4,881) and the output of each plant. or 11% of the total income. Net profit per factory was estimated at Working capital. The lack of Col$2,337,000 (US$3,921), and the timely credit limits sour starch net profit per ton of sour starch was production and its subsequent Col$24,300 (US$41). commercialization. Of the processors, 61% had plans to obtain credit with a bank. This credit was to pay suppliers Cost-to-Benefit Ratio for raw material and to improve the infrastructure, not only for plants that Profitability of cassava starch process both coffee and cassava, but processing was compared with the also housing for the processors. interest that the local agricultural bank (Caja Agraria) pays to savings Often this credit is used for accounts (21% per year in 1991) as a purposes other than those indicated in measure of opportunity cost. The the initial request. The factory is soon return on starch processing was only left without working capital and has to 12%, although the opportunity resort to informal lines of credit such interest was 21%. That is, the as suppliers giving extra days to pay. processor lost 9%. Middlemen may also lend money to the processors, with the compromise Profits generated by this type of that, once the starch is processed, it small enterprise are therefore operative in nature, not financial. Table 2. Constraints to cassava starch Most small-scale, starch processors processing, northern Cauca, Colombia. earn only enough to satisfy their basic needs. Without an economic Constraints Responses by surplus to reinvest in their business, processors processors cannot readily modernize (no.) (%) the infrastructure. Processors Irregular supply 27 57 continue to participate in the market Supply vs. demand for starch 6 12 because their basic necessities and Working capital 6 12 fixed costs are covered and they can Lack of water (climate) 6 12 continue to sustain themselves in Tank capacity 3 6 the market despite the lack of profits Total 48 100 for reinvestment.
37 Cassava Flour and Starch: Progress in Research and Development will be sold to them at favorable Plant site. Starch processors prices. Many loans granted by locate their processing plants middlemen are used to make down according to where land is available, payments to cassava farmers to rather than where consumers are ensure root supplies. situated. Control over the product is therefore lost and the distance Tank capacity. Tank capacities between the two ends of the system are often very limited: on the average, (supply and demand) grows and so a factory will have five fermentation does the chain of middlemen tanks with an average capacity of 1 t participating in the commerce. each, and five sedimentation tanks with an average capacity of 551 kg Starch quality. Processors have each. few standard ideas on starch quality, making it difficult to determine criteria Stock of spare parts. for product quality. For 97% of the Small-scale processors do not keep a surveyed processors, fermentation is stock of spare parts needed to important; this process should take maintain their equipment, often from 15 to 20 days. For 70% of causing holdups in starch production. processors, cassava variety is also a major criterion. But processors tend to select varieties with high starch Commercial Constraints yields rather than for quality, partly because working capital is insufficient Factories are affected by different for purchasing the more expensive, combinations of several major high-quality starch varieties (Table 4). commercial constraints (Table 3); these are: Water. During summer months, water is scarce and, in winter, Transport. Remote rural areas processors have difficulty in drying characteristically have deficient and transporting the starch. For 78% transport facilities, which delay of surveyed processors, water quality deliveries. Starch processors are thus is an important criterion: it should be often obliged to rely on middlemen, cold. The water used by 60% of the which may go against their own surveyed processors comes from interests. streams and is untreated before use,
Table 3. Constraints to cassava starch Table 4. Processors’ criteria for quality in commerce in northern Cauca, cassava starch, northern Cauca, Colombia.a Colombia.
Constraints Factories Criterion Factories using affected criteriona (no.) (%) (no.) (%)
Transport 15 15.2 Color 33 33.3 Location 9 9.1 Fermentation time (acidity) 96 98.0 Availability of raw material 36 36.4 Starch grain 54 54.5 Availability of credit 24 24.2 Cassava variety 69 69.7 Starch quality 33 33.3 Age of cassava 30 30.3 Climate 33 33.3 Water quality 78 78.8 School vacations 21 21.2 Climate 9 9.1 Others 39 39.4 Others 30 30.3 a. Total number of starch factories surveyed a. Total number of starch factories surveyed (weighted data) = 99. (weighted data) = 99.
38 Cassava Starch in Northern Cauca, Colombia:... thus contributing to low product to Cali, capital of the Department. quality. Cali provides resources needed by small-scale starch factories, Processors’ knowledge. The particularly spare parts for equipment limited technical knowledge that and financial resources. cassava farmers have of starch quality, and its processing and Industrial security. Adequate commerce, also negatively affects this industrial security, to reduce risks for agroindustry. employees during processing, does not yet exist within the organizational structure of small-scale starch Social Characteristics Related factories. Processors usually do not to Cassava Starch Production appreciate the risks and diseases that and Commerce can occur during starch processing and rarely take minimum protective The following social issues are measures. involved in the cassava starch agroindustry: Colds comprise the commonest ailment (according to 39% of surveyed Improved living standards for processors), a result of personnel not rural, small-scale, starch producers wearing dust masks during drying and and of the region as a whole. packing (Table 6). The personnel in Table 5 shows that the starch charge of sieving should be fitted with agroindustry benefits both the people gloves and goggles; 27% have suffered directly involved in the industry and either cuts or eye ailments. Drying the entire northern Cauca region. sites located in high places, such as This small-scale enterprise increases the “eldas” (sliding overhead screens), the number of jobs (according to 76% should be constructed with protective of the processors surveyed) and better banisters to prevent fractures and uses available resources in the region, blows. thus considerably energizing the economy of the Valle del Cauca A related problem that affects Department. The region is becoming a production continuity is frequent center of development for the entire “Monday absenteeism” as a result of Department, favored by its proximity hangovers after heavy drinking.
Table 5. How the cassava starch agroindustry contributes to the economic well-being of the individual family and of the region, northern Cauca, Colombia. Responses from a survey of 99 households.
Socioeconomic criterion Family Region
(no.) (%)a (no.) (%)a
Overall improvement 99 100 99 100 Increased education 51 52 Improved housing 69 70 Improved living standards 48 49 Vehicle ownership 27 27 Improved roads 33 Increased income 66 67 Jobs 75 76 Others 21 21 24 24 a. Percentages are rounded off.
39 Cassava Flour and Starch: Progress in Research and Development
Table 6. Incidence of diseases and accidents in For example, CETEC is conducting small-scale, starch factories, northern studies on treating waste waters. Cauca, Colombia.a
Complaint Factory reporting (no.) (%) Conclusions
Ailmentb Some conclusions from the study are: Cold 39 39.4 Backache 3 3.0 (1) Cassava starch production is of Eye problems 3 3.0 major importance in northern Sinusitis 3 3.0 Nonec 27 27.3 Cauca, with 90% of cassava roots produced destined for starch Accidents production. Fractures 9 9.0 (2) Major constraints are, for starch Cuts 27 27.3 production, irregular supply of Blows 3 3.0 Nonec 60 60.6 cassava, lack of timely credit, and maintenance of equipment; for a. Total number of starch factories surveyed starch quality, quality of water (weighted data) = 99. used, fermentation time, and b. A problem that causes absenteeism and variety and age of cassava; for industrial accidents is the hangover. Twenty-four (i.e., 24%) factories reported on this problem. commerce, starch quality, c. That is, the factory either did not know, or did not climate, and transport. answer. (3) Small-scale processors cannot fix starch prices, which therefore obey the laws of supply and demand. Cassava farmers need Environmental contamination. assistance in ensuring a constant About 85% of residues produced supply of roots for processors, during starch extraction are which would help control price deposited in the streams (40%), fluctuations. rivers (27%), and ravines (18%) near (4) Cassava starch production offers the factories. Another 12% is used as socioeconomic benefits such as manure, and 3% enters the sewerage employment. In 1990, 422 people system. As a result, the agroindustry and, in 1991, 345 people were noticeably contaminates the region’s employed. rivers and affects its inhabitants’ (5) Over the long term, this study is health. Even the processors expected to benefit about themselves use this same water for 3,000 households that subsist on washing, drinking, and cooking, as this agroindustry. Once they well as root processing. The understand and efficiently contaminated water also affects manage the production and starch quality and thus the commerce of cassava starch, processors’ income. these families will have better opportunities of participating in Given their usually low the market and improving their educational level, processors do not social well-being. appreciate the importance of caring for rivers or for the adequate disposal of residues. To reduce environmental Recommendations contamination, the departmental government and different institutions The following list of recommendations interested in regional economic and aim to help guide experts intervening social development need to intervene. in technical, economic, and scientific
40 Cassava Starch in Northern Cauca, Colombia:... decisions on behalf of cassava starch measures are draining defined processors. areas and conserving riversides to prevent erosion. (1) Small-scale cassava starch (6) Activities aimed at improving the processors working in rural areas population’s standards of living are should be encouraged to plan also needed in such areas as staggered crops by taking into health, education, housing, and account the vegetative period of public services. the varieties they select. The crop (7) The local government and should satisfy, at least partly, the communities should be factory’s requirements for raw encouraged to provide potable material so that it may reach water for human consumption and equilibrium point or higher. The for use in small-scale, starch remaining amount can be factories. obtained from third parties within (8) Farmer associations should be the factory’s area of influence by encouraged to stimulate their providing incentives to cassava members to negotiate more and farmers. participate in setting cassava (2) Differential prices for cassava starch prices. Farmers would then roots should be fixed, depending have increased financial, operative, on quality and yield. This policy and administrative capacity; be will allow processing plants to able to handle their own trading operate more economically. needs; and better understand (3) Additional technical, financial, market behavior. and administrative support, adapted to the processors’ socioeconomic level, is needed. References The processors can then benefit from real improvements in their Chuzel, G. 1991. Cassava starch: current enterprise’s infrastructure and and potential use in Latin America. Cassava Newsl. 15(1):9-11. organization. (4) Operational schemes that CIMMYT (Centro Internacional de maintain labor and administrative Mejoramiento de Maíz y Trigo), costs at acceptable levels should Programa de Economía. 1993. La be incorporated. The small-scale, formulación de recomendaciones a partir de datos agronómicos. Lisboa, starch factory can then achieve Mexico. equilibrium and will operate acceptably and economically. Pardo Camacho, F. 1991. Diseño estadístico (5) Measures should be taken to de muestreos. Universidad de los improve factory infrastructure, Andes, Santafé de Bogotá, Colombia. thus improving cassava starch de Servín, A. and Servín Andrade, L. A. 1978. production while better conserving Introducción al muestreo. Editorial the waterways. Examples of such Lumusa, Mexico City, Mexico.
41 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 7
CASSAVA STARCH AND FLOUR IN ECUADOR: ITS COMMERCIALIZATION AND USE
Carlos Egüez*
Abstract because either factories were poorly located in relation to production In Portoviejo, Ecuador, the Unión de zones, or national or imported raw Asociaciones de Trabajadores materials were cheaper. In contrast, Agrícolas, Productores y Procesadores small-scale cassava starch extraction de Yuca (UATAPPY) produces cassava dates back to early this century, while starch and flour for a wide variety of flour processing began 8 years ago. products, including animal feed, corrugated cardboard, plywood, About 200 family-run processing cassava bread (pandeyuca), baked units or “rallanderías” currently products, and ice-cream cones. The produce between 2,500 and 4,000 t of amounts of cassava starch or flour cassava starch per year. The incorporated vary according to technology of drying cassava chips to intended use. The most common uses produce flour was introduced from are filling in plywood, carbohydrate Colombia to Manabí Province, source in balanced animal feeds, and Ecuador, in 1985, and has been as binder in cardboard boxes and adopted mainly by the Unión de shrimp feeds. Ecuadorean industries Asociaciones de Trabajadores are beginning to appreciate the Agrícolas, Productores y Procesadores potential advantages of these de Yuca (UATAPPY), which produces products. Recent studies estimate 1,000 to 1,500 t of flour per year. that the potential demand greatly exceeds the current supply, which The Ecuadorean Integrated augurs well for cassava root Cassava Program, consisting of processors. UATAPPY and several national and international institutions, has produced 10 different cassava Introduction products with a wide marketing range, including exports to Colombia over Attempts to produce cassava flour and 2 consecutive years. starch at the industrial level in Ecuador have been unsuccessful, The commercialization of UATAPPY’s products has allowed it to continue its activities. But market expansion and consolidation remains * Cassava Program, Fundación para el difficult as Ecuadorean industries Desarrollo Agropecuario (FUNDAGRO), continue to use other starchy raw Portoviejo, Ecuador. materials that are sometimes
42 Cassava Starch and Flour in Ecuador:...
Table 1. Comparison of current prices of cassava byproducts with wheat flour and maize starch in Ecuador (factory prices).
Cassava product Current price Other product Current price (US$/t) (US$/t)
Cassava meal 175 Sieved whole flour 231 White cassava flour 236 Wheat flour 352 Sieved white flour (for human consumption) 275 Starch (for human consumption) 660 Industrial starch (first grade) 440 Domestic maize starch 400 Standard industrial starch 363 Colombian maize starch 305 (second grade) (placed in Ecuadorean factories) Starch bagasse 113 Bran of sieved flours 88
SOURCE: UATAPPY, 1993, personal communication.
Table 2. Demand for wheat flour and maize starch by several markets, and current sales of cassava products, Ecuador.
Product Market Annual demand (t) Current sales
Wheat flour Balanced shrimp feed 25,000 0 Lumber industries 2,400 256
Maize starch Cardboard factories 6,000 0 Colombia ? 200
SOURCE: Susan Poats, 1993, personal communication. subsidized, such as wheat and Descriptions and Uses of maize starch (Table 1). Cassava Products and Byproducts1 Persuading industrial managers to use cassava products— Cassava meal is a coarse, brown sometimes the same product— powder obtained from unpeeled chips, instead of traditional materials for a sun-dried on concrete, and ground in wide variety of individual uses has a hammer mill. It is used as a also been difficult (Table 2). carbohydrate source in balanced feeds, and as a pellet binder in shrimp The situation is improving, feed, replacing wheat flour and however, with the current “free synthetic binders and forming market” conditions, which allow 2%-12% of the formula, depending on cassava products to be more the manufacturer. competitive in terms of quality and price. 1. The cassava products and their uses as described here are not registered; they reflect the author’s research at processing and industrial levels in Ecuador.
43 Cassava Flour and Starch: Progress in Research and Development
Sieved whole flour is a very fine White bran is a coarse white off-white powder obtained by sieving powder that is a byproduct of meal through a no. 60 mesh. It is processing for white table flour. It is used in plywood, replacing 35%-40% used as a fiber source in feeds for of wheat flour (17% of the formula). livestock and pigs.
White industrial-grade flour is a Whole bran is a coarse, brown coarse powder made from peeled powder that is a byproduct of chips, sun-dried on concrete, and processing for sieved whole flour. It is hammer-milled. It is used as pellet used as a fiber source in feeds for binder in shrimp feed. livestock and pigs.
White table flour is a very fine white powder obtained from peeled UATAPPY’s Production and roots that have been treated, chipped, Markets tray-dried, and sieved through a no. 60 mesh screen under hygienic Since the program was established, conditions. It is suitable for human UATAPPY has marketed more than consumption, used to partially replace 8,000 t of cassava products for wheat flour in cones for ice cream different uses (Tables 3 and 4). (25%-30%) and in noodles (10%). The 50 t of cassava meal produced during the first year were sold to First-grade industrial starch is a poultry-feed plants, replacing maize very fine, very white powder obtained grain. Since then, both markets and from peeled cassava roots that have products have become more been rasped, washed, sedimented, and diversified. Ten products are now sun-dried on concrete. It is used as marketed, for three to five different pellet binder in balanced shrimp purposes, depending on annual feeds, and in cardboard boxes, negotiations (Tables 3 and 4). replacing maize starch by as much as 100%. Between 1986 and 1989, cassava meal was almost the only Second-grade industrial starch is of product, finding a ready use as a lower quality than first-grade starch, shrimp feed binder. Between 1989 because the protein fraction remains. and 1990, cassava meal for shrimp It is used in balanced shrimp feeds feed was still being produced, but and cardboard boxes, replacing maize important industries began to starch by as much as 100%. demand cassava flour without peel. Since then, this market has been Starch for human consumption is a the most important, accounting for very fine white powder obtained from 87% of the total volume produced. peeled roots that have been rasped, washed, sedimented, and dried on In 1990-1991, UATAPPY’s total paper under hygienic conditions. It is production volume increased by 70% used in bread, milk products, bakery over that of the previous year. But products, and sausages. the percentage of UATAPPY’s total produce destined for the shrimp feed Ground bagasse is a coarse, market fell from 87% to 71% as two white-yellow powder that is a new markets opened up: sieved byproduct of starch extraction. It is whole flour for the plywood industry, used as a carbohydrate source in and starch for the cardboard balanced feeds, and in shrimp feed, industry. combined with meal and starches.
44 Cassava Starch and Flour in Ecuador:...
50
543
115
1,743
1,106
1,015
1,033
1,003
byproducts
Total annual
production of
--
--
--
--
--
--
- 26 1,522
4 -
5 -
9 26 8,129
consumpt.
purchase human bagasseand products
Starch
2nd
1st and consumpt.
------
- - 11 4 - -
- - - 5 - -
------
33 - 70 10 24 -
21 - 89 25 56 -
meal consumpt.
Flours
) by UATAPPY, Manabí, Ecuador, 1985-1993.
a
meal white sieved human
Indust. Indust. Indust. Sieved white Bran Indust. Human Bagasse Indust. Purchase Purchase cassava
17 - 300 512 -
(no.) roots
Assns. Fresh
c
b
1985-86 2 - 50 - -
1986-87 4 19 96 - -
1987-88 10 28 500 - -
1988-89 16 - 1,100 - -
Year
Table 3. Total amount of cassava processed (t
Total 17 47 3,199 3,003 662 93 149 410 67 203 261
a. Values rounded to metric tons. b. Production estimated for the crop year 1 July-30 June. c. Preliminary data, subject to confirmation.
SOURCE: Susan Poats, 1993, UATAPPY Socioeconomic Monitoring Survey. 1989-90 16 - 304 574 -
1990-91 17 - 258 982 200 6 52 119 2 51 69
1991-92 17 - 464 304 170 - 17 20 4 12 37
1992-93 17 - 127 631 292 33 80 101 17 60 155
1993-94
45 Cassava Flour and Starch: Progress in Research and Development
Table 4. UATAPPY markets and their share of cassava products, Ecuador.
Year Product Volume Market Share (t) (%)
1985-86 Meal 50 Poultry feed 100 Total 50 1986-87 Meal 96 Shrimp feed 83 Treated roots 19 Export human consumption 17 Total 115 Shrimp feed 2 1987-88 Meal 500 Shrimp feed 92 Treated roots 28 Export human consumption 5 Industrial starch 11 2 Starch human consumption 4 Bread making 1 Total 543 1988-89 Meal 1,100 Shrimp feed 99.5 Starch human consumption 5 Bread making 0.5 Total 1,105 1989-90 White flour 574 Shrimp feed 57 Meal 304 Shrimp feed 30 Industrial starch 70 Shrimp feed 7 White flour Sieved flour human 33 3 consumption 10 Bread making 1 Starch human consumption 24 Bovine feed 2 Bagasse 1,015 Total 1990-91 White flour 982 Shrimp feed 56 Meal 258 Shrimp feed 15 Sieved whole flour 200 Plywood 11 Industrial starch 188 Cardboard industry 11 Bran 52 Bovine feed 3 Bagasse 51 Shrimp feed 3 Starch human consumption 6 Bread making 0.5 Sieved white flour human 6 0.5 consumption 1,743 Total 1991-92 Meal 464 Shrimp feed 45 White flour 304 Shrimp feed 29 Industrial starch 57 Shrimp feed 5 Sieved whole flour 170 Plywood 17 Bran 17 Bovine feed 2 Bagasse 12 Bovine feed 1 Starch human consumption 9 Bread making 1 Total 1,033 1992-93 White flour 631 Export to Colombia 42 Industrial starch 292 Export to Colombia 19 Sieved whole flour 256 Plywood 17 Meal 127 8 Bagasse 86 6 Bran 80 Bovine feed 5 Sieved white flour human 33 Ice-cream cones 2 consumption 17 Sausages 1 Starch human consumption 1,522 Total
SOURCE: UATAPPY, 1993, personal communication.
46 Cassava Starch and Flour in Ecuador:...
In 1992-1993, the Colombian (2) Cassava products compete well in market was the main client: 600 t of terms of quality and price with white flour and 200 t of second-grade other raw materials, except for starch were exported. Although their maize starch, which is cheaper use has not yet been confirmed, they imported from Colombia. appear to have been used to make (3) “Free market” and “open border” adhesives. conditions favor the commercialization of cassava products. Constraints to Commercializing Cassava Products Bibliography
The major constraints are: Brouwer, R. 1992. The cassava flour demand in the plywood industry in Ecuador. Wageningen, the Netherlands. (1) Poor product quality, resulting from contamination at one or more CENDES (Centro de Desarrollo). 1993. of the processing stages (most Estudio de mercado para conocer la important in relation to the more demanda potencial de productos profitable, but more demanding, elaborados de yuca. Unión de Asociaciones de Trabajadores markets). Agrícolas, Productores y Procesadores (2) Seasonality of supply (UATAPPY de Yuca (UATAPPY) and CENDES, can only produce during the Quito, Ecuador. 8 “summer” months as the cassava is sun-dried). Egüez, C. 1992. Informe anual del Programa de Yuca, 1992. Fundación para el (3) Competition from other raw Desarrollo Agropecuario (FUNDAGRO), materials, especially maize starch Portoviejo, Ecuador. that enters Ecuador from Colombia at low prices (Table 1). ______. 1993. Revisiones de los archivos (4) Lack of knowledge: industries do del Departamento de Contabilidad de la UATAPPY, 1985-1993. Unión de not yet know how to substitute Asociaciones de Trabajadores wheat flour or maize starch with Agrícolas, Productores y Procesadores cassava products. de Yuca (UATAPPY), Portoviejo, Ecuador.
Conclusions
(1) The current supply of cassava products is small in relation to the potential demand.
47 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 8
CASSAVA PRODUCTS FOR FOOD AND CHEMICAL INDUSTRIES: CHINA
Jin Shu-Ren*
Abstract cassava must also increase—most effectively by developing the range of Cassava is grown in China basically as its products through adopting and a food security crop. But, in the last expanding secondary processing 20 years, yields have increased sharply techniques. in answer to demand from small-scale and, more recently, large-scale industries. Since the 1980s, China Changes in Cassava has seen rapid development in the Processing commercial prospects of a wide range of cassava derivatives, including During the 1960s fructose-series products, sorbitol, maltol, fermentation products (such Cassava processing in China was as alcohol, MSG, and citric acid), mainly small-scale: production groups denatured starch, glucose, and of 20-30 families in rural areas would glucose syrup. A hillside crop, cassava plant cassava in unused areas or on plays a key role in the economy and sloping land as insurance for food agroindustry of southern China. scarcity. Because such land was However, local economies and usually of low fertility and received no production in poorer rural areas fertilizer, cassava yields were low: in urgently need modernizing if they are the 1960s, in Guangxi, China’s largest to fully benefit from these new cassava-producing area, the average developments. Recommendations are yield per mu (1 mu = 665 m2 or made regarding appropriate scale and 15 mu = 1 ha), expressed as dried technology, given the various chips, was only 46 kg, that is, about constraints (e.g., transportation 0.7 t/ha. The area planted to cassava through hilly terrain and seasonal varied from year to year: in 1967, in availability of fresh roots). Relevant Guangxi, cassava was grown on economic factors are also reviewed. 1,054,000 mu. Because of climatic Through improved cultivars and constraints, cassava is a seasonal crop, farming practices, cassava yields can and the small-scale processing plants increase significantly. But, to operated only 3 to 4 months a year. encourage production, the value of The major product was poor quality starch.
Cassava was processed by first * Guangxi Nanning Cassava Technical Development Center (GNCTDC), Nanning, crushing fresh roots in a grinder and Guangxi, China. allowing the resulting mash to settle in
48 Cassava Products for Food and Chemical Industries: China water. The starchy mass was then Production capacity of some factories strained through a fine-mesh cloth reached 10 t/day. Guangxi had more bag to separate the starch, which was than 270 starch factories, although then sun-dried and pulverized. the total output was low—probably less than 80,000 t, or less than Some high-quality starch was also 300 t/factory. produced, although outputs were low. Fresh roots were crushed in a grinder; During the 1980s passed through a second, finer, grinder, and then through a vibrating, Cassava production improved or octagonal, sieve that removed markedly, because: coarse residues; and, finally, passed to an open-ended, horizontal-flow, (1) More land was made available in sedimentation trough that was rural areas; 30-50 m long, 35 cm deep, and 40 cm (2) Farmers were allowed to plant wide. High-density impurities, such high-value crops, leading to major as sand and gravel, were deposited increases in the area planted to first, starch farther toward the middle cassava; of the trough, and low-density (3) As the production of other crops impurities, such as fiber and protein, improved, cassava’s role shifted at the far end, or flushed out. The away from being a food security starch was then removed from the crop to providing raw material for trough, dewatered by centrifugation, animal feed and industry; dried, and pulverized. If desired, a (4) As the national economy developed, bleaching agent, such as potassium the demand for starch increased; chlorate or hypochlorite, was added and before the starch entered the trough. (5) Capital and imported equipment were made more readily available. Starch was produced from fresh cassava for only 3 to 4 months a year. The combination of these factors During the rest of the year, dried created an unprecedented expansion in cassava chips were used, requiring an the scale and technology of cassava additional 1 to 2 days of immersion in production. water (or longer in cold weather) before filtering. During fine grinding, an The last five years additive would be introduced to improve the starch extraction rate. The two main cassava-producing areas in southern China now have several Most of the cassava not used for large-scale starch factories. By 1992, starch extraction was used as pig feed. at least 10 factories had an output The roots were first peeled, soaked in capacity of 40 t/day, the largest water to remove hydrocyanic acid, and capable of producing 60 to 80 t. then boiled. Overall, the factories produced more than 30,000 t. Three types of factories During the 1970s co-exist:
The technology of producing (1) Plants newly constructed or quality cassava starch improved. The adapted, and using domestic wooden lining of the trough was technology. Features include a replaced by marble or glass, the roller cleaner, two-stage crusher, centrifuge assumed a horizontal rather countercurrent-washer, rapid than vertical structure, and a crank blancher, whirlpool sand remover, sieve replaced the octagonal sieve. dish-separator, dewatering
49 Cassava Flour and Starch: Progress in Research and Development
centrifuge (sometimes imported), By 1992, cassava starch and two-stage forced-air drier. production in southern China Product quality and cost efficiency accounted for 23% of the national are adequate. Such factories production. Cassava yields had account for 25% of cassava starch increased notably, the regional total produced in China. exceeding 1,200,000 t of dried chips. (2) Plants where equipment and Yield per mu increased to 500 kg for technology are entirely imported, fresh cassava and 200 kg for dried for example, from Japan, Germany, chips. and Thailand. Features include a needle grinder, high-pressure Secondary processing crank sieve, whirlflow separator, centrifugal layer-separator, water Since the 1980s, the Government has remover, and airflow drier. shown more interest in developing Although they produce cassava products derived from high-quality starch, such plants secondary processing. Cassava are economically less viable development and utilization are listed because of high equipment costs among the key projects of the sixth and associated steep depreciation. 5-year plan drawn up by the State In addition, they compare Science and Technology Commission. unfavorably in performance when Several national centers are also dried cassava chips are used in involved in the development and seasons when fresh roots are utilization of cassava, including the unavailable. Guangxi Nanning Cassava Technical (3) Small-scale, low-technology Development Center (GNCTDC). factories that, technologically and economically, compare poorly with (1) and (2). The average Developing Cassava Products starch-extraction rate is estimated for Food and Chemical as being 20% lower. Because Industries these factories currently account for about half of southern China’s Industries began using cassava-based annual starch production, their products, developed from secondary technology urgently needs processing, during the 1980s. These modernizing. include:
With fresh cassava available for Fructose-series products only 3 to 4 months a year, the use of dried chips has been inevitable, even Fructose emerged in the 1970s as a though costs are higher, the starch of healthier alternative to sucrose. poorer quality, and the recovery rate Technology using starch as a raw lower. To counter these problems, a material was developed soon after, and technology has been recently adopted 1980 saw the first factory, with an that would produce “high starch, high annual fructose output capacity of extraction, and high storage.” It 10,000 t, set up in central China. The involves bulk-buying fresh cassava technology of “third-generation” when starch content is at its highest, fructose (i.e., fructose containing not and crudely processing the roots into a more than 10% glucose) has since “paste pool.” The starch can therefore been mastered in China. Through a be extracted in due course, extending collaborative project, the GNCTDC the annual period of cost-effective, finished testing a pilot plant in 1986, optimal quality starch production from and, in 1992, set up the first 3 to 5 months. industrial plant to produce crystalline
50 Cassava Products for Food and Chemical Industries: China fructose. Third-generation fructose is mannitol, which is then purified by used medically, in cases of glucose crystallization. Mannitol is used contraindication. Clinical tests on medically in blood-vessel diastolic 100 diabetic patients given 25-50 g of preparations, as a dehydrating agent, high or crystalline fructose showed no and in the treatment of cerebral significant changes in blood sugar thrombosis and other circulatory level. Thus, its safety, sweetness, disorders. In industry, it can be used pleasant taste, and few calories make as raw material for the production of fructose particularly suitable for polyester, polyethylene, and solid-foam diabetics. plastics.
Maltol. A sugar alcohol, maltol is Chemico-industrial products produced by incomplete hydrolysis of starch, using the enzyme maltase, and Sorbitol. A hexan-hexol, sorbitol subsequent hydrogenization. It is a is made from glucose by syrup that is as sweet as sucrose, and hydrogenization in a high-pressure is used in confectionery. reactor. Because it readily absorbs moisture, it can replace glycerine in Fermented products the manufacture of toothpaste, cosmetics, and oil-based paints. It Fermented cassava products form a serves as raw material in the sizeable industry in China, and include manufacture of vitamin C by alcohol, monosodium glutamate (MSG), fermentation, first into hygric acid and and citric acid. Cassava wine was then into ascorbic acid. Every ton of produced in the 1960s when grain was ascorbic acid produced requires scarce, but has now become obsolete 2.7 t of sorbitol. More than 10 sorbitol because of poor quality. factories operate in China, the largest of which has an annual production Alcohol. After 2 days of capacity of 13,000 t. A unit capable of fermenting, the alcohol content in 30,000 t is being planned, while some cassava can reach 10%-11%. Most have recently begun using continuous- factories were established in the 1970s hydrogenization technology. and have an annual output capacity of 10,000 t. New factories with a Production of solid sorbitol 30 to 50-thousand-ton capacity are (3,000 t/year) has been successfully now being planned. Sugarcane and established in Nanning, Guangxi. cassava growing areas usually coincide Glucose produced from cassava chips and cassava alcohol is almost always is hydrogenized under high pressure produced by sugar mills, which use (continuous process) to produce liquid molasses during the sugarcane season sorbitol. The liquid is concentrated to (November-April) and, using the same 98 Brix, seed crystals are introduced, equipment, cassava roots for the rest and the sorbitol spray-dried and of the year. Because cassava is low in crystallized. Solid sorbitol is easier to protein and nutrients needed for transport and store. growing yeast (the fermentative agent), it must be supplemented. A mixture of Mannitol. Another hexan-hexol, cassava and molasses is often used to but with little moisture-absorption good effect. capacity, mannitol is usually a byproduct of iodine extraction from MSG. Also known as gourmet kelp. But it can also be produced powder, MSG is a popular flavor commercially by hydrogenizing enhancer in Chinese cuisine. National fructose, of which 50% converts into production exceeds 200,000 t/year. Of
51 Cassava Flour and Starch: Progress in Research and Development these, about 25,000 t are obtained in medicine) and glucose syrup from cassava starch, which first (DE42) (confectionery). More than undergoes acid hydrolysis, and is then 100,000 t are produced annually. supplemented with growth factors and left to ferment for 4 or 5 days. During this time, ammonia salt is added Market for Cassava continuously. When the glutamic acid Products content reaches 7%-8%, the mixture is filtered and the acid precipitated by While the Government does not iso-electric points. The acid is then restrict sales within China, it controls purified by ion exchange, neutralized exports. Fresh cassava or dried to produce the sodium salt, and cassava chips are sold to domestic crystallized. markets by farmers or by local supply-and-marketing cooperatives. Citric acid. In China, citric acid The higher value chips are cut 0.5 to is mainly produced by fermenting 1.0 cm thick, peeled, and sun-dried. sweetpotato. In 1990, more than The price of fresh cassava sold to 80,000 t were produced. Recently, factories varies according to season, however, citric acid is increasingly starch content, and transportation being produced from molasses and distances. More recently, prices have cassava, using an Aspergillus strain, been affected significantly by grain known as Citrobacter, which was prices. Cassava starch costs developed by the Shanghai Industrial 10%-15% less in winter, the Microbiology Research Institute. production season, than at other Cassava starch liquefies easily to a times, reflecting the fact that most low-density liquid and, after a 4-day factories are small-scale and lack fermentation, the citric acid content capital. exceeds 15%. An extraction rate of more than 92% is possible. The short In total, about 500,000 t of fermentation period, and ease of cassava (based on dried chips) are liquefying the starch and extracting used in starch production, 80% from the acid keep production costs low. fresh roots and 20% from dried chips. The glucose industry uses the largest Denatured starch amount of starch (55%), followed by MSG production (20%), family Since the 1980s, research on consumption (4%), and sales to denatured starch has developed northern China or abroad (11%). rapidly, allowing some processes to become industrialized. The current Only about 15% of the cassava annual yield of denatured cassava grown is used for alcohol and other starch is about 7,000 t, and includes products. Alcohol producers in acid-denatured starch, α-starch, cassava-producing areas have access ethylic starch, phosphate ester starch, to, and prefer, molasses from and co-polymerized starch. Although sugarcane. In northern China current outputs are low, the future transportation difficulties constrain prospects of this industry are alcohol producers from buying promising. cassava.
Glucose and glucose syrup Citric acid production accounts for about 3% of cassava grown. Crystalline glucose in southern China is produced primarily from cassava About 600,000 t of dried cassava starch, as are injection glucose (used chips are exported annually, but much
52 Cassava Products for Food and Chemical Industries: China is used locally as animal feed, both in The rapid development of industry traditional form and, more recently, in in China provides an ideal opportunity compound feeds. for cassava. Yields of starch increased five-fold between 1981 and 1989 as the Although yields increased sharply annual growth rate exceeded 15%. in the 1980s, processing remained Those industries using starch as a raw backward and markets were few. More material, such as MSG, maltol, recently, however, the processing glucose, and fructose, anticipate rapid industry has been modernizing and expansion while the domestic market supply and demand have increased in remains unsaturated. Because tandem. maize-growing areas are far from cassava-producing areas, cassava has the advantage of lower transportation Opportunity and costs. While the price differential is Competition maintained, cassava has the advantage in southern China. The development of cassava production and processing in China, already The market for cassava products is inhibited by strong domestic grain potentially rich, particularly for production, is further restricted by the denatured starch, which is still new. natural coupling of major cassava and Although the use of cassava starch in sugarcane producing areas. Thus, foodstuffs is currently limited, its market prices of sugarcane largely future potential is high. dictate the extent of cassava farming. Furthermore, where sugarcane yields are high, markets stable, and farmers Conclusions and experienced producers of sugarcane, Suggestions cassava is unlikely to be planted in preference. However, where land is Cassava, a hillside crop, plays a key less fertile and cane yields low, role in the economy and agroindustry cassava’s potentially higher production of southern China. Cassava products is more attractive. are important both in their own right and as industrial raw material. Their Although its starch is used as an future development is integral to that additive in cooking, cassava is rarely of the economy of rural and poorer used as a food in China. Most cassava areas. Two objectives should be is destined for the textile, paper pursued in parallel: to increase yields, making, and chemical industries, and to raise the value of cassava. For where it must face competition from the first, emphasis must be given to maize products. importing and adapting improved varieties, developing farming Cassava’s future prospects are technology, and improving fertilizers. good, even though production yields The second objective requires are still low: about 500 kg of fresh commitment to developing cassava roots per mu (or 200 kg per mu of dried products such as those discussed chips). Although most farmers still use above. If cassava is processed only an old variety, Nanyang Red, fresh at the primary level and commands cassava yields may eventually reach 2 only basic prices, then its prospects or 3 t per mu with the adaptation of are severely limited. Governmental imported improved varieties. That is, policy in this area must therefore improved technology would increase promote research into secondary the current average yield per unit area processing techniques to accompany by an estimated 500%. the improvement of cassava cultivars.
53 Cassava Flour and Starch: Progress in Research and Development
The modern cassava starch not need a high degree of automation factory, in scale and in the technology nor large factories (which are employed, should correspond closely penalized by higher transport costs), to local needs and to take account of and is readily adaptable to local rural such factors as transportation conditions. difficulties, and seasonal variations in production and availability of fresh Most cassava industrial activity in roots. The small, largely undeveloped China has so far been related to factories of southern China urgently high-value products, such as MSG need modernization. At present, and sorbitol, and, although progress is Chinese-manufactured machinery is evident in some areas, effort is adequate for such factories, whereas required in others, especially in the investment in expensive machinery development of denatured starch. from developed countries can increase Given realistic processing and production costs out of proportion to technological transformations, cassava benefits in output and quality. has much to offer the farmers and Secondary processing of cassava does local economies of southern China.
54 Thai Cassava Starch Industry:...
CHAPTER 9
THAI CASSAVA STARCH INDUSTRY: ITS CURRENT STATUS AND POTENTIAL FUTURE1
Boonjit Titapiwatanakun*
A Brief History tonnage). Most of the starch was exported to USA and Japan, and the Early development byproducts to Malaysia and Singapore. Cassava starch exports Cassava first came as a subsistence increased every year from about crop, probably to southern Thailand, 29,000 t in 1955, peaking at through Malaysia, from West Java in 227,000 t in 1961, and dropping Indonesia. Industrial cassava slightly in 1973. processing began in the 1920s in Chonburi Province, on the Eastern No published data are available on Seaboard. The first plants used a domestic cassava starch consumption, simple sedimentation process to but it was probably less than the extract starch, which was destined amount exported, indicating a highly mostly for household consumption. At export-oriented industry that the end of World War II, starch milling developed in response to export was introduced, thus catalyzing the markets. development of Thailand’s now modern cassava starch industry. Entering the animal feed market Most of the starch was exported, together with certain byproducts. The value of cassava starch exports increased to 220 and 223 million baht In the early 1950s, starch was in 1960 and 1965, respectively, but, cassava’s most important export as exports of cassava products for product. In 1955, for example, animal feed expanded rapidly, their 54,122 t of cassava products were percentage share of the total value of exported, with a total value of cassava exports decreased from 76% 69.1 million baht. Of this value, in 1960 to 33% in 1965. cassava starch accounted for about 76% (i.e., 54% of the tonnage) and Thailand began processing byproducts about 22% (i.e., 44% of cassava for animal feed in the late 1950s in response to heavy demand (triggered off by the Common Agriculture Policy) for nongrain feed ingredients (NGFI)—including cassava * Department of Agricultural and Resource products—from the then European Economics, Faculty of Economics, Kasetsart Economic Community (EEC, now the University, Bangkok, Thailand. European Union). In 1957, cassava 1. No abstract was provided by the author. byproduct exports to the Netherlands
55 Cassava Flour and Starch: Progress in Research and Development and the then West Germany were The Agreement slowed down the 1,400 and 7,000 t, respectively. industry’s development, and created the need to explore new ways of using At first (1955-1968), Thailand the cassava root and its products, exported, as animal feed ingredients, particularly as starch. cassava byproducts, meal, and chips; during 1969-1982, native or soft Modified starch pellets were exported; then from 1983 to the present, hard pellets. These Even with Bangkok as a significant products evolved as efforts were market, Thailand was already made to minimize transport costs exporting native starch to USA and and contamination during loading Japan, who processed some of it into and unloading. Such evolution the more valuable modified starch. In reflects the increasing efficiency of Thailand, the earliest processing of the industry’s marketing system, native starch into modified starch stimulated by coordination with, and (glucose syrup) was in 1950, followed technological transfer from, by monosodium glutamate (MSG) in importing countries. 1960. In the late 1970s, USA and Thailand collaborated to produce Exporting cassava products for modified starch for export, followed by animal feed had a significant joint ventures with European and socioeconomic impact on Thailand, Japanese firms. At the same time, for example, farm income, exporters of cassava for animal feed employment, and foreign exchange integrated with native and modified earnings all increased. The area starch processing enterprises. planted to cassava increased dramatically from 38,400 ha in 1957 When modified-starch processing to 171,000 ha, producing 2.6 million began in Thailand, it was typically a tons, in 1968. Although about 75% closed industry, but with the need for of the expanded area first occurred in new export products, the industry Thailand’s eastern region, by 1977, opened up to the extent that even the northeast was producing more plants in cassava-producing areas are than 50% of the national production. producing modified starch, using The starch industry also benefited, simple processing techniques. Plants setting up plants in the new areas. using more complex techniques to produce chemically modified starch The increased export trade also are located mostly in the provinces encouraged the development of around Bangkok, where most equipment that enabled high-speed industries that use modified loading of pellets, and permitted starch are located. Seventeen specialization within the export modified-starch plants, with an business. Thai exporters could set estimated total capacity of up trading companies in the EEC, 300,000 t/year, were operating in thus opening up investment 1990, producing about 250,000 t. opportunities in the industry. The Thai modified-starch industry In July 1982, however, the EEC, developed rapidly during the last through a Cooperation Agreement decade, because, first, the with the Kingdom of Thailand on international trade in native starch cassava production, marketing, and was hampered by import barriers, trade, set an annual maximum of imposed to protect domestic native 5 million tons of imports of Thai starch industries. In contrast, few cassava products as animal feed. import barriers operated against
56 Thai Cassava Starch Industry:... modified starch. Second, Thailand’s (chips and pellets), which were mostly impressive economic growth during exported, and 5-6 million tons were 1980-1990 made possible the processed into cassava starch. investment in high-level technology for processing. Third, modified starch Statistics on starch production are provided an outlet for the foreseeable not available, although the Thai overproduction of cassava, caused by Tapioca Flour Industries Trade the EEC’s restricted imports of Association (TTFITA) estimates that cassava pellets. the total cassava or native starch production was about 1.2 million tons in 1989, 1.3 million in 1990, and Production, Marketing, and 1.4 million in 1992. Price Formation As for many agroindustries, the Root and starch production total number and capacity of cassava starch plants are not updated by During the past decade, data from the official sources. Official records, Ministry of Agriculture and especially those of the Ministry of Cooperatives (MOAC) showed that Industry (MOI), register data as plants total cassava root production are established, but conduct few increased from 19 million tons in 1983 surveys for updating. For example, to about 20 million tons in 1992, that MOAC reported the total number of is, at an annual growth rate of only starch plants in 1970 as 50 and in 0.7%. Yield per ha decreased from 1973 as 128. The MOI then reported about 18 t in 1983 to 14 t in 1992, 146 plants in 1978, but, in 1987, only mainly because fertilizers were not 82, with an estimated capacity of applied in most cassava-growing 1.5 million tons. Although, in 1990, areas, especially in the northeast. the number dropped further to 45 plants—a decrease of 45% (Table 1)— The national average production the estimated capacity dropped only costs per ton of cassava increased 13% to 1.3 million tons. from 450 baht in 1989/90 to 470 in 1990/91 and 540 in 1991/92. The The starch industry may have national average farmgate price per suffered from overcapacity since ton (i.e., the price received by 1978. Even in 1990, the industry cassava growers) was 620 baht in operated for only 8 months. If the 1990, 830 in 1991, and 770 in industry were to operate 10 or 1992. Between 1990-1992, the 11 months/year, then its potential average farmgate price increased by production would be 1.7-1.9 million 24%, which compares with a tons of starch. The capacity of some production cost increase of 20% plants could be expanded, especially during the same period. Cassava in the eastern and northeastern farmers made, on the average, a regions. profit of 253 baht/t. But if production costs continue to increase During 1978-1990, the number of at their current annual growth rate starch plants in the eastern region of 7%, the competitiveness of Thai decreased dramatically from 121 to cassava products in the future world 17, whereas in the northeast it market will be jeopardized. increased from 12 to 22, suggesting a shift of cassava-producing regions During the last 5 years, about from eastern to northeastern 14-15 million tons of root were Thailand, as the animal feed market processed into animal feed products expanded.
57 Cassava Flour and Starch: Progress in Research and Development
Table 1. Number of cassava starch plants and productiona by region, Thailand, 1989 and 1990.
Region 1989 1990
Plants Production Plants Production (no.) (1,000 t) (no.) (1,000 t)
Northern 4 39 4 39 Western 2 27 2 27 Eastern 18 263 17 263 Northeastern 23 936 22 1,024
Total 47 1,265 45 1,353 a. Annual production figures were estimated by multiplying the daily capacity of plants by 240 days.
SOURCE: TTFITA, various years.
But plant numbers may have satiated, and then to chip-and-pellet dropped as the many small, plants. family-operated businesses, using old and mixed technologies, lost out in the Two major outlets are available for competition with modern plants, native starch: (1) domestic which had comparatively higher consumption, and (2) export. production efficiency. Most modern Domestic consumption includes starch plants were constructed by foodstuffs and industrial use local firms, and more than 80% of the (discussed below), but also raw materials and machinery used for material for domestic modified-starch construction were locally produced plants located in provinces around and assembled. Thai firms even built Bangkok. Their products, however, starch plants in Indonesia. are mostly exported. Native starch is sometimes sold as wet starch to Marketing and price formation modified-starch plants located in cassava-producing regions. The marketing of cassava roots is simple: through local truckers to In terms of market share, starch both chip-and-pellet and starch has been more or less equally divided plants. Because the Government between export and domestic allocated quotas of exports to the consumption for the last 5 years. But EEC, based on accumulated stock in prices of domestic native starch are 1988, the price of roots was strongly influenced by export markets determined by that of chips and for both native and modified starch. pellets during the time exporters Prices in importing countries compete were accumulating their stock and with prices of other starches, before stock checking. Once stock especially maize, and the eventual checking was over, root prices were prices reached, in turn, influence Thai more or less determined by native domestic prices. starch prices. When domestic prices of starch were high, following high In the domestic market, native world prices, then only those roots starch is, comparatively, the that could not meet starch content cheapest starch available and used requirements would be sold to the at costs that comprise a relatively chip-and-pellet plants. In other small percentage of the value of the words, roots are sold first to the final products. This enables starch plants, until their demand is domestic industries that use native
58 Thai Cassava Starch Industry:... starch to absorb price fluctuations Current and Future Domestic without seriously affecting the price Use and Export of the final product. Domestic use The links among prices for modified starch, native starch, and Overall, domestic use of cassava roots are shown in the following list of starch can be classified into either 1990 average prices, and marketing food or nonfood industries. No official and processing costs, obtained from a records are available of the total 1991 industry survey: cassava starch consumption by both groups. In 1991, an industrial survey was conducted by the Thailand Items US$/ta Development Research Institute Foundation (TDRI) to compile and Modified starch price c.i.f., Japan 405.0 estimate starch consumption for that Freight and insurance costs, year, and to project future use. Thailand-Japan 45.0 Modified starch price f.o.b., Bangkok 360.0 Starch consumption was Exporting costs 20.0 estimated by calculating the Modified starch prices at plant, percentage of starch consumption per Bangkok 340.0 unit of final product, whether food or Processing costs of modified starch, nonfood. The total starch including 5% weight loss 117.8 consumption of each final product was Native starch prices at Bangkok plant 222.2 then computed by multiplying the Transport costs, Nakhon-Ratchasima percentage use by the total annual and Bangkok 9.0 production of each final product. The Native starch prices at plant in annual total cassava-starch Nakhon-Ratchasima 213.2 consumption for producing the final Processing costs of native starch products was obtained during the (conversion rate of starch to survey as a discrete series. The root = 1:5) 52.0 complete series was then constructed Value of roots per ton of starch at plant 161.2 by using growth rates between Value of wastes (10% of the value periods. of roots) 16.1 Total value of roots per ton of starch Once the series of starch at plant 177.3 consumption data was constructed, Price of roots per ton (root prices at the future consumption of starch of the plant in Nakhon-Ratchasima) 35.5 each product was forecast by a simple Production costs of roots in 1989/90 demand projection equation: (published by MOAC) 17.6 ______a. Exchange rate is 25.50 baht = US$1.00 (1994). D = R + NY (1)
where:
The above list also shows the D = growth rate of quantity relationships between Bangkok prices demanded for the final and Nakhon-Ratchasima Province product prices for native starch and roots. R = growth rate of population (the Under normal conditions, cassava annual population growth rate, starch plants derive their daily buying estimated by the TDRI as 1.3%, price of cassava roots from this type of for 1991 to 2001 was used) information.
59 Cassava Flour and Starch: Progress in Research and Development
N = income elasticity of demand for 1n(STl) = -16.043 + 1.749 1n(GDP) (2) starch for the final product (-9.125) (9.034) 2 (using the 1972 per capita R = 0.950 income as the base year) D.W. = 1.244 Y = growth rate of income per where: capita, using 1972 as the base year (the TDRI projection of STl = per capita demand for starch 6.4% for 1991 to 2001 was in producing MSG and lysine used) GDP = per capita income in the 1972 base year The estimate of starch consumption for each final product is The growth of demand for starch discussed below: to produce MSG and lysine can be approximated by equation (1). That is, Food industries if D = 12.617% (or 1.33 + 1.75 x 6.45), then starch consumption for Monosodium glutamate and producing MSG and lysine in 1991 = lysine. In 1991, three MSG plants 97,977 t (87,000 x 1.12617). operated: Ajinomoto, Raja, and Thai Churos. In 1960, Ajinomoto set up the Sweeteners (excluding fructose). first MSG plant in Thailand and was Domestic production of glucose syrup the first to use modern technology to began in 1950, glucose powder in modify cassava starch. Ajinomoto is 1976, and sorbitol in 1980. The also the only MSG plant to use cassava conversion ratio of each product and starch as the major raw material, the estimated annual production which it does at a rate of 2.4 t of starch obtained from the survey are as per ton of MSG. The other two plants follows: use molasses.
Product Ratio of Estimated annual In 1986, the Ajinomoto group set cassava production of up the first and only lysine plant, not starch to final product just in Thailand, but also in Southeast product (tons) Asia. To produce lysine, the plant Glucose syrup 1:0.92 30,000 consumes cassava starch at the same Sorbitol 1:1.20 28,000 rate as for MSG.
To produce both MSG and lysine, The glucose syrup producers the Ajinomoto group consumed estimated that sweetener production 28,000 t of cassava starch in 1980; consumed 28,040 t of cassava starch 33,000 t in 1985; and 87,000 t in in 1950; 42,060 t in 1980; and 1990. Growth rates were 3.3% during 70,100 t in 1990. Based on these 1980-1985, and 21.4% during data, a statistical series of cassava 1985-1990. Based on these data, a starch consumption data was statistical series of starch consumption constructed, and the income elasticity data for MSG and lysine production of demand for starch was estimated at during 1980-1990 was constructed. 1.16. The annual growth rate of These data were used to estimate the demand for sweeteners was calculated income elasticity of demand for starch at 8.812%, which was used to project for MSG production, that is, 1.75. The demand for cassava starch for estimation equation, of which the producing sweeteners (but not autocorrelation was corrected, was as fructose), during 1991-2001. follows:
60 Thai Cassava Starch Industry:...
Pearl sago. Pearl sago or tapioca for starch was calculated at 0.64. was produced by many small, and a Equation (1) was used to project few large, cassava starch plants. In future starch consumption. 1990, the TTFITA listed 12 pearl-sago plants, five of which were large. But Nonfood industries many small, family-operated plants may not have been counted. Paper industry. In 1989, the Processing involves mixing cassava Thai Pulp and Paper Industries starch with water, pearling the Association (TPPIA) reported that mixture, and sun-drying it. The 38 paper mills were operating, 12 of conversion rate of cassava starch to which received the Board of pearl sago is 1:0.9. Starch Investment (BOI) privilege. The total consumption was about 23,000 t in annual capacity was 870,000 t of 1986 and 30,000 t in 1990, an annual paper, proportioned as follows: growth rate of 6.7%. Pearl-sago 521,000 t in kraft paper; 193,000 in producers expect that the rate will be printing and writing paper; 110,000 in maintained for the future, because paperboard; and 46,000 in sanitary both domestic and export markets are paper. Although Thailand imports expanding. The 6.7% growth rate was newsprint, by the end of 1993, three therefore used to project cassava plants with total annual capacity of starch consumption in pearl-sago 300,000 t were operating. processing. Of these five types of paper, only Household consumption. Three the plants producing kraft paper, kinds of starch are consumed by the printing and writing paper, and household: rice starch, sticky rice paperboard used cassava starch as a starch, and cassava starch. Total raw material in production. The starch consumption was reported at average consumption rate of starch 7.12 kg/person per year. Assuming was about 5% of the total paper equal proportions of starch weight, with paper production consumption, then per capita cassava expanding at a rate of 13% per year. starch consumption would be 2.37 kg. From these data, cassava starch A statistical series of household starch consumption in the paper industry consumption data was constructed for was estimated at about 42,000 t in 1991-2001 by assuming a constant 1990, and projected by using a 13% per capita consumption at 2.37 kg annual growth rate. and using the TDRI’s population projection. The constant was Plywood industry. In 1990, approximated from a household 35 plywood manufacturers were survey conducted by the Office of operating. One piece of plywood uses Agricultural Economics, MOAC, about 370 g of cassava starch. As far during 1970-1971. as can be ascertained, the average metric ton of plywood contains Other food industries. Cassava 80 pieces. Total plywood production starch is used as a raw material or tends to be underreported because ingredient by canning and other food logs are imported illegally from industries that make, for example, neighboring countries. More accurate instant noodles, vermicelli, sauces, estimates may be obtained by soups, sausages, and candies. The examining the relatively constant annual cassava starch consumption plywood market share of the Thai was estimated to be 17,960 t in 1980 Plywood Company Limited, a state and 31,986 t in 1990. Based on these enterprise, which share held at 10% data, the income elasticity of demand during the last few years. Estimates
61 Cassava Flour and Starch: Progress in Research and Development for cassava starch consumption were before weaving, at about 1% of the 4,775 t in 1989, 6,924 in 1990, and warp’s total weight. Modified starch is 6,700 in 1991. also used in dyeing, an industry that is not yet well developed in Thailand. For the next 3 years, the annual The estimated current consumption of cassava starch consumption in the cassava starch in the textile industry plywood industry may stay at about is therefore minimal. A statistical 6,700 t, because, first, importing logs series on cassava starch consumption from neighboring countries will data was constructed for 1985-1990, become difficult as these countries and used to estimate a simple trend establish their own plywood industries regression. The simple trend equation and the prices of logs rise. Second, is as follows: other boards are substituting plywood, such as hardboard, medium board, STH = 9657.5 + 816.5 Y (3) medium density fiber board (MDF), t-vale = (26.699) (6.182) and soft board. Some of these R2 = 0.9508 products are made from sugar fiber. D.W. = 2.0012 Third, the comparative advantage in plywood production of Thailand will where: decrease over the years as that of Indonesia and Malaysia increase. STH = total annual cassava starch Fourth, some plants are replacing consumption cassava starch with phenolic resin, which provides a better adhesive Y = year 1985 = 1 quality. Total cassava starch consumption in the plywood industry Other industries. Other will therefore decrease by 30%-40% industries that use cassava starch as from the 1993 level and then remain a raw material are those that stable until year 2000. manufacture glues, paper products, and chemicals. The estimated cassava Textile industry. Cassava starch starch consumption are about is applied to the yarn in the warp 15,000 t in 1980, and 60,000 t in
Table 2. Projected consumption of cassava starch by Thai food and nonfood industries.a
Industry 1991 1996 2001
Food-processing industries 375,071 (73) 516,463 (70) 772,819 (65) MSG and lysine 97,977 (19) 170,456 (23) 322,194 (27) Glucose syrup 76,375 (15) 113,368 (15) 177,490 (15) Pearl sago 32,060 (6) 44,690 (6) 62,295 (5) Household consumption 134,908 (26) 144,582 (19) 153,645 (13) Other food industries 33,751 (7) 43,367 (6) 57,195 (5) Nonfood industry 136,151 (26) 226,357 (30) 411,634 (35) Paper 47,098 (9) 86,776 (12) 159,879 (13) Plywood 6,700 (1) 2,010 (<1) 2,010 (<1) Textiles 14,557 (3) 18,640 (3) 22,722 (2) Other industries 67,796 (13) 118,931 (16) 227,023 (19) Total 511,221 (100) 742,818 (100) 1,184,453 (100) a. Figures in parentheses are rounded percentages of the total.
SOURCE: TDRI, 1992.
62 Thai Cassava Starch Industry:...
1990, indicating an annual growth Exports and major markets rate of about 15%. This growth rate was used to project future As mentioned above, export markets consumption of cassava starch. for Thai cassava starch strongly influence domestic price formation. Estimates of cassava starch The future prospects of export markets consumption in Thailand are are therefore highly significant for the presented in Table 2. In 1991, about development of, not only the starch 511,221 t of cassava starch was industry, but the entire cassava consumed, 73% of which was industry in Thailand. consumed by food industries and households. When the data are On the whole, the starch industry broken down, household consumption has been export oriented since the is highest with 26%, followed by MSG 1940s. Although the quantities of and lysine (19%), sweeteners exported cassava starch have (excluding fructose) (15%), “other food fluctuated, an upward trend is industries” (7%), and pearl sago (6%). obvious. Data from the TTFITA show that exports of cassava native and Nonfood industries consumed modified starches increased from 136,151 t of cassava starch or 26% of 459,048 t in 1985 to 656,291 in 1990. the total. “Other nonfood industries” Exports to Japan increased from consumed the highest percentage 143,619 to 204,572 t, and to Taiwan (13%), followed by paper industries from 124,926 to 248,434 t. That is, (9%), textile industries (3%), and the export share of Japan and Taiwan plywood industries (1%). increased from 58% to 69% of all exports. These countries are expected The estimated total domestic to remain major export markets in the starch consumption in 2001 is future. 1.18 million tons. Although starch consumption by nonfood industries Japan. Although data from the will have increased to more than Japanese Ministry of Agriculture show 400,000 t (35% of the total), most that Japan’s total annual starch domestic starch consumption will still consumption increased from be in the food industries (65%). 2.4 million tons in 1986 to 2.7 million Among the industries, the in 1990, other sources suggest that MSG-and-lysine industries will Japan consumes at least 3.5 million consume the most (27%), followed by tons of starch annually. The Japanese “other nonfood industries” (19%), Government has set 0.2 million tons sweeteners (15%), and paper as the maximum annual import quota industries (13%). for starch to protect the domestic starch industry, which is based on The fructose industry used sweetpotato and white potato. 9-15 thousand tons of cassava starch during 1988-1990. Once existing food Starch in Japan is consumed regulations permit the use of fructose mostly by manufacturing and in the domestic soft drink industry, processing industries, especially for then demand for fructose will increase syrup dextrose (60%). Other by about 20% per year. This will industries, in descending order, are mean an extra 17,600 t of cassava chemicals (including medicines) or starch in 1991; 38,000 in 1996; and modified starches, fibers, foodstuffs, 92,200 in 2001. paper and adhesives, beverages,
63 Cassava Flour and Starch: Progress in Research and Development fish-paste products, and MSG. starches were imported at much Sources of starches are maize (79%), higher rates than the set ceiling. white potato (10%), sweetpotato (5%), Imported modified cassava starch imported starch (4%), and wheat must compete with domestic starch and/or flour (2%). Some of modified starch made from maize. the products of processing are re-exported. Thailand’s competitive position in the Japanese market is determined The manufacturing and by its status in two categories: first, processing industries are not only the the native starch market, in which major consumers of starch, but they Thailand still has the strong are also the major importers, advantages of low prices and especially the syrup dextrose continuous supplies; and, second, producers, modified-starch the modified-starch market, in which processors, re-export processing Thailand faces not only competition industries, and manufacturers of from domestic modified starch, but MSG, medicines, and adhesives. also from modified starch imported from the EEC (which makes it from In 1990, the average wholesale low-priced starch, itself imported prices of starch in Japan showed that from Eastern Europe). Future native cassava starch was the prospects in the Japanese market, cheapest (Table 3). If there were no however, depend heavily on Japan’s import barriers, cassava starch trade protectionist policies. imports would increase tremendously. Taiwan. Being a newly developed industrialized Imported modified starch is country, with a rapidly growing subject to an 8% import duty if from economy, Taiwan has had to developed countries. Although restructure its agricultural sector. developing countries pay 0% tariff, From producing basic raw materials, they face an import ceiling, imposed it now produces high-value products by the Japanese Government since such as fruit and those from 1989. The ceiling is based on a total livestock and fishery. Consequently, value per year. During the early Taiwan expects to import more of stages of implementation, the both raw and finished agricultural Japanese Government was flexible, products. Although Taiwan does not and some groups of modified impose a tariff import barrier on cassava starch, it does on imported cassava products (Table 4). Table 3. Average wholesale prices of starches in Japan, 1990. Thai cassava starch products have good prospects in Taiwan, Starch Price where Thai exporters and concerned (yen/kg) governmental agencies have actively Domestic starches produced from: promoted cassava products in the Sweetpotato 65.00 Taiwan market. White potato 140.00 Maize 62.00 Projections of cassava starch Imported starches exports to Japan and Taiwan, and Native cassava starch 33.00 of total exports. Simple linear White potato starch 63.00 trends (Table 5) were used to project cassava starch exports to Japan SOURCE: TDRI, 1992. and Taiwan, and in total. The
64 Thai Cassava Starch Industry:...
Table 4. Import duties imposed on cassava will reach about 1.82 million tons products by Taiwan. (9.1 million tons of roots), of which HS code Tariff rate domestic consumption would account for 41% (data not shown). In 2001, 0714.10 Manioc (cassava) 20% total demand would increase to 1108.14 Manioc (cassava) starch 17% or 2.6 million tons (13 million tons of NT$1,200/t roots), of which domestic consumption 1903.00 Tapioca and substitutes 17% or would account for 46%. The future of prepared from starch NT$1,306/t the cassava starch industry will
3505.00 Dextrins and other 7.5%-20%a therefore still be export oriented. modified starches 7.5%-17%b a. Imposed for all countries. Scenario of Future b. Applied to countries with reciprocal benefits, such as Thailand. Industrial Adjustment
SOURCE: TDRI, 1992. As mentioned earlier, the EEC’s Common Agricultural Policy (CAP) Table 5. Projected cassava starch exports to triggered off the development of Thai Taiwan and Japan and total exports cassava products for the animal feed (in tons), Thailand, 1993-2001. industry. The EEC has been the only major market for these products, a Year Taiwan Japan Total exports result of the EEC’s high cereal prices. 1993 355,673 259,837 872,614 Hence, any changes in the CAP will 1994 390,922 278,065 939,709 have a strong impact on the Thai 1995 426,171 296,293 1,006,805 cassava industry. Analyses of CAP 1996 461,420 314,520 1,073,901 reforms will therefore be imperative for 1997 496,668 332,748 1,208,093 predicting the industry’s future 1998 531,917 350,976 1,275,189 prospects and development. 1999 567,166 369,204 1,342,285 2000 602,415 387,431 1,342,285 The CAP reforms 2001 637,664 405,659 1,409,381 Overall, the CAP has fulfilled the SOURCE: TDRI, 1992. EEC’s objective of reaching self-sufficiency in food, but at the high price of subsidizing the agricultural projection of total starch exports, sector. The CAP also created several however, did not include the problems, especially the possibility of new markets, such as overproduction of cereals, and South Korea’s paper industry. At livestock and dairy products, which present, cassava starch imports under cost more than ECU 79,000 million. the international HS code 1108.14 are not restricted by South Korea. One reason for the overproduction Another potential market is Russia, if of cereals was their reduced use in the special export credits can be made animal feed industry, which available to Thai exports through the substituted the highly priced cereals establishment of an export-import with cheap NGFI imports. The EEC bank. At least 10,000 t of cassava has tried to limit and reduce NGFI starch would then be exported. imports by setting quotas for cassava imports from Thailand, Indonesia, Based on the above estimates, Brazil, and China. Many other NGFI demand for cassava starch in both products, however, were imported domestic and export markets in 1996, without restrictions or tariffs.
65 Cassava Flour and Starch: Progress in Research and Development
As well as the problems created by Impact of CAP reforms on prices of the CAP, the EEC also has had to face cassava products and roots pressure from the GATT Uruguay Round of trade negotiations to The CAP reforms will probably liberalize trade. CAP reforms were strongly effect NGFI imports, therefore inevitable—concentrating on especially those providing sources of decreasing agricultural subsidies to energy in animal feed, such as reduce grain and meat surpluses. The cassava products. As cereals become strongest impact on NGFI imports cheaper, substitutes will be used less. came from the drastic decrease of The EEC commission reported that the intervention prices for cereals, which substitution effect would be severely reduced domestic wholesale 6-7 million tons (EEC, 1993b). prices of cereals. Three major changes from the existing system occurred: Given the price relationship of ECU 24 per ton between wheat and (1) Agricultural support shifted from cassava products used in compound being solely price subsidies to feed in previous years, Thai cassava being compensatory payments to products are expected to be producers; competitive in the EEC market and to (2) Measures for increasing be consumed by the animal feed production for self-sufficiency were industry at the current rate of about no longer emphasized; and 5 million tons. Prices, however, would (3) Free trade was encouraged while decline to the following levels: maintaining the basic principles and instruments of the CAP. Season Wholesale prices of cassava Under the CAP reforms, cereal products in the EEC (ECU per ton) prices will change as follows: 1993/94 93
(1) Buying-in prices and intervention 1994/95 84 prices will be the same for every cereal; and 1995/96 76 (2) From the 1993/94 season (July) onward, all cereal prices (ECU per However, the above price levels ton) will be: show the worst scenario. Given the exchange rate of ECU 1 = US$1.19 and US$1.00 = 25.30 baht, farmgate Season Intervention Target Threshold pricea priceb pricec prices of cassava roots in Nakhon Ratchasima Province, Thailand, would 1993/94 117 130 175 be as follows: 1994/95 108 120 165
1995/96 100 110 155 Season Farmgate prices in Nakhon Ratchasima a. The price at which the EEC is prepared to buy Province, Thailand cereals if the market price is below it. b. The price the EEC wants producers to receive US$/ton baht per ton (and consumers to pay). The EEC will intervene through import levies (taxes) or by buying 1993/94 22.81 577.14 surpluses to ensure that prices do not fall below the target level. 1994/95 18.78 475.26 c. The price at which cereal imports enter the EEC, 1995/96 15.93 403.00 i.e., the world price plus the variable import levy.
66 Thai Cassava Starch Industry:...
Based on MOAC statistics, the compound feed industry and of the national average cost of producing Thai export industry to the CAP cassava roots in 1991/92 was reforms, which dropped export prices 540 baht/t (US$21.34/t). This for cassava products for animal feed in implies that farmers received only the EEC. Consequently, producers of 37.14 baht/t (US$1.47/t) in cassava chips and pellets had to lower 1993/94, and that, in 1994/95 and their buying prices for roots. As root 1995/96, farmgate prices will be less prices decreased, root supplies also than production costs. Obviously, if decreased. these price levels become reality, cassava farmers will switch to other The immediate impact of CAP crops. reforms on the Thai cassava starch industry was to create competition Also obviously, hard pellet prices among cassava starch plants to obtain in Rotterdam (ECU 76-93/t) and root the cheapest root supplies. This prices in Nakhon Ratchasima meant that, if cassava farmers delayed (US$15.93-22.81/t) will discourage their harvests, root prices would Thai exports to the EEC. That means increase in the short run. But, if the quota rent of export quota in the prices of cassava products in the EEC EEC will vanish, making it difficult for dropped to ECU 93/t, then exports to Thai exporters to export pellets to the EEC in 1993/94 would be reduced non-EEC markets at such low prices drastically. Eventually, surpluses of that they would obtain export quota to cassava roots would develop and the EEC and thus sell pellets at high prices will drop below 700 baht/t in prices. In fact, current non-EEC 1993/94. markets for Thai pellets are subsidized by the quota rent to the EEC. These If prices remain at 700 baht/t (or markets are not potential markets for US$27.67/t), which would give a net cassava pellets, unless cereal supplies farmgate price of 580 baht/t become drastically short and world (US$22.92/t), farmers would find it prices of high-protein ingredients for unprofitable to grow cassava. For animal feed (soybean meal) become example, the 1993/94 root production very low. costs in Nakhon Ratchasima were 578.50-664.80 baht/t Impact of CAP reforms on root (US$ 22.87-26.28/t). This implies supplies to the Thai cassava starch that cassava root production will begin industry decreasing.
This section tries, perhaps The Thai Department of prematurely, to project what would Agriculture reported that production happen if exports of Thai cassava costs for cassava would decrease to products as animal feed to the EEC 509.00 baht/t (US$20.12/t) if farmers were decreased drastically. The followed appropriate agricultural projection is based on observations of practices and used the new Rayong events in Nakhon Ratchasima 60 variety. Trade associations of Province. Nakhon Ratchasima Province are now working closely with concerned After the new CAP was governmental agencies to provide implemented in July 1993, buying extension services for cassava farmers prices for roots offered by plants in the to encourage them to adopt new province decreased from 740 baht/t in agricultural practices and varieties. July to 700 in October. This was a Extension services, however, are not result of adjustments in the EEC’s sufficient if farmgate prices are not
67 Cassava Flour and Starch: Progress in Research and Development high enough. To ensure their raw EEC market. Cassava starch plants material supplies, therefore, cassava would have fewer operational days and starch plants have begun contract higher average production costs. To farming. overcome such problems, the plants may either increase capacity per day, To avoid cassava root surpluses, or minimize production costs wherever the Government had already, in early possible. 1993, launched a program to encourage farmers to reduce planting The first alternative may be areas (now totalling 400,000 rai, or possible by merging plants. Thus, 64,000 ha). It is still too early to only large and efficient starch plants assess the program’s success, but will survive, and their operations cassava production will decrease in would also be further integrated with any case, if the above price level of high-value processing activities such 700 baht/t is realized for 1993/94. as modified starch. The plants may also be forced to diversify into Cassava starch plants will commodity trade. therefore face problems of root supplies, and their period of operation Production costs may be may become smaller than 8 months if minimized through joint efforts in contract farming and extension obtaining special rates from services for improved varieties and governmental authorities for utilities agricultural practices are not realized. such as electricity, which accounts for more than 35% of total processing As the production of cassava costs. products for animal feed decreases, the cassava market will become Governmental policy dominated by starch plants operating in cassava-producing areas. During Although concerned governmental peak seasons, local starch plants will agencies realize that the CAP reforms not be able to buy all available roots. will generate negative impact on the Root prices will therefore drop to levels Thai cassava industry, especially for at which chip-and-pellet plants find animal feed, the only policy so far profitable to start their operations. implemented is that of reducing Thus, a new market equilibrium of cassava planting areas. Short- and root prices will be established at long-term policies for the cassava levels profitable for farmers and industry are yet to be formulated. In chip-and-pellet producers. The level addition, the Government has still to will depend heavily on the export decide whether to renew or renounce prices of chips and pellets and on the Agreement, which will expire in domestic demand for these products. 1994, between Thailand and the EEC Even so, both farmers and starch on cassava exports. plants would mutually benefit from setting up a system that regulates root supplies. Summary, Conclusions, and Recommendations Starch processing The cassava starch industry has As low prices and decreasing demand developed largely under a free market for roots force reductions in cassava system, with limited governmental production, the root marketing period intervention. The EEC’s CAP triggered will shorten and adjust to the seasonal off the rapid development of cassava demand for cassava products in the exports for animal feed in the 1970s,
68 Thai Cassava Starch Industry:... causing the whole industry to shift In the early 1990s, fewer than from starch processing to the 50 cassava starch plants were processing of cassava exports for actively operating, with a total animal feed. capacity of about 1.4-1.6 million tons of starch per year. This Although, by percentage, the compares with the 2 million tons proportion of cassava starch exports to that 84 plants produced in the late total cassava exports decreased from 1980s. Of the plants remaining, 17 25% in 1966 to 11% in 1991, starch were modified-starch plants, with an exports themselves increased at an estimated capacity of 300,000 t/year annual growth rate of 5.5%. USA and and an actual production of Japan have formed the major market 250,000 t. for Thai cassava starch since 1966, despite competition with domestic Domestic cassava starch maize starch. During the 1980s, consumption was projected (as Taiwan became the third most described in “Current and Future important market for Thailand, using Domestic Use and Export,” p. 59-65) Thai starch in modified-starch to the year 2001 as almost processing and other industries. 1.2 million tons. Domestic consumption and use in food In 1982, the EEC-Thai Cooperative processing will decrease to 18%. Agreement was signed; it set a Use in textiles will decrease to 2%, maximum import quantity of and in plywood to 0.2%. In contrast, 21 million tons over 4 years. The starch consumption in the Agreement also obliged Thailand to manufacture of MSG and lysine will actively search for other uses of increase to 27%, and in the paper cassava, finally settling on industry to 13% (Table 2). value-added cassava starch, that is, modified starch, for Japan. Total cassava starch use in 1991, that is, the sum of total Cassava starch was already domestic consumption plus total produced for domestic consumption, exports, was more than 1.2 million both as food and industrial raw tons. It may increase to more than material, and, in relatively larger 2.5 million tons by the year 2001, quantities, for export. In 1965, the assuming Japan and Taiwan as the estimated total domestic consumption only two major export markets. was 44,557 t, and exports were 148,206 t. During 1965 to 1980, Despite the fact that domestic starch was used mostly in food consumption of cassava starch has industries (27%), the manufacture of increased over time, domestic prices MSG (22%), paper industry (16%), and depend heavily on export prices, household consumption (16%). especially those of modified starch in recent years. For the future, the Thailand’s outstanding economic cassava starch industry, and the performance during 1980-1990 in both cassava industry as a whole, will industrial and agroindustrial sectors still be export oriented. The EEC’s drew the attention of cassava starch CAP reforms, which reduced entrepreneurs to the domestic use of domestic cereal prices by 29% for starch and its potential. During July 1993 to June 1996, will 1990-1991, a survey was carried out to therefore strongly influence the Thai estimate domestic starch consumption cassava industry. in various Thai industries, and to project starch use in the next decade.
69 Cassava Flour and Starch: Progress in Research and Development
The impact of reduced cereal (1) Research on new uses for both prices in the EEC (to ECU 117/t in cassava roots and starch should be 1993-1995) on Thai pellet prices in carried out as a joint effort between Rotterdam was to reduce them to private and public sectors; ECU 93/t. This reduced price, in (2) Research on cost-reduction turn, reduced the farmgate price of technologies in cassava production cassava roots in Nakhon Ratchasima should be enhanced and Province, Thailand, to US$23/t in disseminated to farmers as soon as 1993/94, only slightly above possible; production costs. These reduced (3) Coordination and cooperation prices may make the cassava starch between public and private sectors industry the major buyer of roots in should be strengthened through the domestic market. frequent dialog and consultation; and But if the CAP reforms drastically (4) Short- and long-term governmental decrease the exports of Thai cassava policies on the cassava industry as products to the EEC, then cassava a whole should be formulated. production would decrease in the future, creating problems of supplies for cassava starch plants. To Bibliography overcome these problems, starch plants and cassava farmers may find EEC (European Economic Community), that contract farming would be Commission of the European mutually beneficial. Communities. 1993a. Agriculture in the GATT negotiations and reforms of the CAP. Brussels, Belgium. Despite the uncertainty of the kind of impact the CAP reforms will have on ______. 1993b. CAP reforms and the GATT the Thai cassava industry, both compatibility. DG VI. Brussels, Belgium. domestic cassava starch consumption Jones, S. F. 1983. The world market for starch and starch exports are likely to and starch products with particular increase. As a whole, the Thai reference to cassava (tapioca) starch. cassava industry is an Tropical Development and Research export-dominated industry that has Institute (TDRI), London, UK. faced many trade restrictions. The TDRI (Thailand Development Research Institute outcome of the GATT Uruguay Round Foundation). 1992. Cassava: a scenario of trade negotiations will strongly of the next decade. Bangkok, Thailand. influence the cassava industry, (In Thai.) especially the starch sector. Titapiwatanakun, Boonjit. 1983. Domestic tapioca starch consumption in Thailand. Each cassava-producing country In: TTTA year book 1982. The Thai should take this opportunity to review Tapioca Trade Association (TTTA), the potential of its cassava starch Bangkok, Thailand. industry in terms of its economic comparative advantage over other ______. 1985. Analysis of the short- and long-run demand and supply prospects starches produced domestically and of of tapioca products: report submitted its international economic comparative to UN/ESCAPE. Bangkok, Thailand. advantage. TTFITA (Thai Tapioca Flour Industries Trade As far as the future development of Association). 1989. Thai tapioca industries. Bangkok, Thailand. the Thai cassava industry as a whole, and its starch industry in particular, ______. Various years. Thai Tapioca is concerned, the following Association yearbook. Bangkok, recommendations are suggested: Thailand.
70 Sweetpotato Flour and Starch:...
CHAPTER 10
SWEETPOTATO FLOUR AND STARCH: ITS USES AND FUTURE POTENTIAL1
Nelly Espínola*
Introduction 6.0 t/ha of dry matter, depending on the variety (Ruiz et al., 1980). It can In terms of production, sweetpotato also be grown as a perennial crop, (Ipomoea batatas) is the fifth most tolerating foliage cutting every 3 to important crop in developing countries 4 months, depending on where it is (Table 1). Latin America, its place of origin, paradoxically accounts for only 1.8% of world production (Table 2) Table 1. Food crop production in developing (Scott, 1992). countries, 1961-1988.
In Peru, this root crop is used Crop Production (thousands of tons) mainly for direct human consumption (96%) and its foliage or lianas are fed Paddy rice 449,968 to animals (90%). In other countries, Wheat 214,119 like the Philippines, the tender parts of Maize 184,927 the foliage are also eaten as a Cassava 137,412 vegetable (Woolfe, 1992). Sweetpotato 125,359 SOURCE: Food and Agriculture Organization of the In China, the world’s leading United Nations (FAO), Basic Data Unit, unpublished data. producer of sweetpotato, its use has varied over the last 20 years, decreasing for human consumption (from 60% to 40%), and increasing for Table 2. Sweetpotato production in developing animal feed (30% to 45%) and countries by region, 1961-1988. industrial use (5% to 10%). Region Production About 90% of sweetpotato foliage (thousands of tons) (%) is used for animal feed. Although it has a low carbohydrate content, its Africa 6,263 5.0 (Sub-Saharan) 6,192 levels of fiber, protein, and vitamins are higher, thus stimulating milk Asia production in cattle. Sweetpotato (China) 116,811 93.1 production may vary from 4.3 to 108,062 Latin America 228 1.8
Total 125,359 100.0 * Physiology Department, Centro Internacional de la Papa (CIP), Lima, Peru. SOURCE: Food and Agriculture Organization of the United Nations (FAO), Basic Data Unit, 1. No abstract was provided by the author. unpublished data.
71 Cassava Flour and Starch: Progress in Research and Development grown (either coastal regions or This paper reviews sweetpotato highlands) (Beaufort-Murphy, 1993, processing at rural and industrial personal communication). levels for both human and animal consumption; and the effects its A new variety is to be released to promotion would have on production, farmers; it is high yielding for forage, rural and urban employment, savings with high leaf protein content in foreign exchange, and stimulating (up to 19% dry base) and very low agroindustrial activity. trypsin-inhibitor content. This variety can also be grown in the highlands during the dry season when natural Unprocessed Sweetpotato pastures become scarce. In Peru, sweetpotato is boiled, fried, In a study carried out in Peru, the baked, or mashed. Its raw roots can be costs of cultivating sweetpotato were grated and used to make bread or found to be lower than those of other sweets like camotillo. Sweetpotato roots crops like potato and maize. It can be can also be used in cattle feed as raw harvested two or three times a year chips mixed with fibrous feedstuffs. and so is considered a staple crop for Animals seem to find sweetpotato both human and animal consumption palatable, searching in their mixed feed (Achata et al., 1990). to consume it first.
As a food product, sweetpotato is a A dairy in the Cañete River area, source of energy, proteins, provitamin the largest sweetpotato producing A (β-carotene), vitamin C, and iron. It region of Peru, used sweetpotato in its ranks among the crops generating the cattle feed, thus considerably highest carbohydrate content per increasing the daily milk production hectare (156 MJ/day) over a relatively from 25-26 L/head (1992) to 30 L/head short period (120 days), even when low (1993) (Espínola, 1992). levels of fertilizer and pesticide are applied. Bread made with sweetpotato purée The germplasm bank at the Centro Internacional de la Papa (CIP), Peru, is Bread is an important item in the a source of important genetic diversity Peruvian diet, but imports of wheat with great potential for improving the flour for bread making are costly. Since crop for human and animal the 1960s, researchers have sought consumption and industrial purposes. ways of substituting wheat flour with sweetpotato flour. The Universidad Peru has some experience in Nacional Agraria “La Molina” and a sweetpotato cultivation, but this crop is bakery in Chincha (near Lima), for grown mainly in countries like Japan, example, have started manufacturing China, Vietnam, and the Philippines, composite-flour specialty breads, both where it is used in foodstuffs, animal loaf and cake-type, which include feed, and industry. Sweetpotato boiled, peeled sweetpotato, substituting processing is increasing in importance as much as 40% of the wheat flour in these countries and considerable (Peralta et al., 1992). information is available on the topic. If this information were adapted to Bread made with raw, grated Peruvian conditions, it could yield sweetpotato rapid results, making investment in sweetpotato products comparatively Peru. The use of raw, unpeeled, cheaper than that in other crops. grated sweetpotato to make an
72 Sweetpotato Flour and Starch:... economic bread is being introduced; Flour: Peru sweetpotato substitutes for 30% of the wheat flour. A “grainy” bread is If sweetpotato varieties with a high obtained, with a slightly sweet taste, dry-matter and starch content, and a resulting from the very sweet low oxidation rate are processed, a commercial varieties used. Its higher percentage of flour is recovered nutritional quality is similar to that of (Table 3). traditional bread made with 100% wheat flour (Denen et al., 1993). CIP CIP is collaborating with the is collaborating with the Universidad Universidad Nacional Agraria “La Nacional Agraria “La Molina” to Molina” to test both sun- and improve this sweet bread’s recipe, oven-dried flour in poultry rations. The appearance, shelf life, and crumb (or optimal level of maize substitution and “grain”) size. Initial efforts, in which the better type of flour (raw or cooked) the peel was discarded and the roots will be determined. In another study, finely grated, succeeded in substituting with pigs, conducted by the same as much as 50% of wheat flour university, oven-dried sweetpotato was (20% dry base) with sweetpotatoes. used to determine the optimal substitution level, according to animal Burundi. Bread preparation with age. raw, grated sweetpotato was introduced to Burundi, eastern Africa, Commercial production of where the technology was adapted. sweetpotato flour, supported by the White varieties, with dry matter private sector, is just beginning, and contents ranging from 25% to 30%, new products for subsequent were used to replace 30% of the wheat commercialization are being developed. flour. Modifications included fine Commercially, sweetpotato flour can be grating of peeled roots, oil instead of used to substitute wheat flour in bread lard, and the elimination of enhancers. making or maize flour in balanced Egg whites were added as a final feeds (in 1992, maize imports were touch, to give the bread a look similar more than US$82 million). to the Peruvian pan de yema. Sweetpotato flour will be analyzed to identify its chemical components and Costs were lower than for 100% contaminants, and to determine its wheat bread but the selling price was digestibility and potential uses in the same. This meant a higher profit human and animal consumption. for the baker and a reduced use of wheat flour, with subsequent savings Companies are producing in foreign exchange (Berrios and sweetpotato flour through a novel, Beavogui, 1992). low-cost industrial process that processes the roots either continuously Processed Sweetpotato
Processed sweetpotato products Table 3. Percentage of flour recovered from different varieties of sweetpotato. include snack foods, such as fried chips and caramel-coated chips, and Country Variety Flour yield industrial products such as (%) sweetpotato flour, purée, and starch. Philippines Georgia Red 12.0 A large variety of starch-based Ilocos Sur 37.0 products exists, and Japan has given high commercial value to raw Peru Jonathan 28.6 (commercial variety) sweetpotato starch.
73 Cassava Flour and Starch: Progress in Research and Development
(500 kg/h), taking 8 to 10 min; or in ingredient for instant soups and batches (less than 500 kg/h), taking traditional breakfasts. 45 to 60 min. Flour yield for commercial sweetpotato varieties is Peru. The sweetpotato processing 28.6%, that is, 3.5 kg of fresh industry is just beginning and only sweetpotatoes produces 1 kg of flour one company is producing flakes from (Vásquez, 1994). sweetpotato purée under the commercial trade name “Menú.” This First, sweetpotatoes are selected, product can be used to prepare baby then washed and peeled foods or school breakfasts, but high mechanically, only partially removing production costs are still a constraint peel and foreign material by abrasion. (Denen et al., 1993). Milling, that is, rasping the root at high velocity, follows. A very fine product is obtained, which is then Sweetpotato starch pressed to eliminate water, resulting in a pressed cake with 38% moisture. The granule size of sweetpotato starch Some solids containing starch, is similar to that of cassava, with only β-carotene, sugars, and proteins are 5% of the total being very small and eliminated with the water but are colloidal, and easily lost during water later recovered by decanting and extraction. Both sweetpotato and incorporated into the flour during cassava starches, when submitted to drying. The flour is dried at 40 °C for X-ray diffraction, have type-A 8 seconds in a current of hot air structures commonly found in cereals. produced by propane gas (for table The ratio of amylopectin to amylose is flour) or by carbon briquettes (for 3:1 and, in some cases, 4:1 (Woolfe, animal feed). The flour is packed in 1992). 50-kg plastic bags through a feeder hopper. Gelatinization temperature and type are important in feed formulas, Production costs for a volume of varying with variety. Gelatinization 700 t are US$150/t, and the selling temperatures from 58 to 69 °C, 58 to price is US$190/t. To maintain 75 °C, and 65 to 80 °C have been optimal sanitary conditions, stainless reported. The degree of association steel materials are used in the between molecules is much greater equipment. than in potato and similar to that found in cassava. Purée Raw sweetpotato starch is much Philippines. Because this more resistant to the action of process involves advanced technology, digestive enzymes (2.4%) than are high-quality varieties should be used maize (9.2%) and wheat (17.6%) to obtain a maximum yield. starches. The degradation time of Developed countries, such as the USA raw sweetpotato starch is 15% in 6 h or Japan, produce sweetpotato purée compared with 20% for cassava and on a large scale. In the Philippines, a 10% for yam. Amylose degradation powdered product for preparing capacity increases when starch sweetpotato mash and “Cantonese” granules are ruptured, improving in noodles, has developed through a pelletization (animal feed) and collaborative project between the reaching a peak in cooking. national agricultural program and Visayas State College of Agriculture Asia. In countries like China, (ViSCA). This powder is also the main Taiwan, and the Philippines,
74 Sweetpotato Flour and Starch:... sweetpotato is grown on small farms, (or Chinese noodles) commonly used in where the raw roots are cut into long the dish chifa. chips or flakes and sun-dried. The dried product is then sent to distilleries Three different methods of starch and starch factories for further extraction are employed, with differing processing. percentages of recovery: the water precipitation method (12%-14%); the In Korea, Taiwan, and Japan, natural precipitation method about 8%, 16%, and 28%, respectively, (16%-18%); and the liquid acid method of the sweetpotato production is used (17%-20%) (Timmins et al., 1992). as raw starch in the food industry, for making bread, biscuits, cakes, juices, Residues are peelings and fiber, ice cream, and noodles. The starch is which are fed to pigs either directly or also converted into glucose syrup or after fermentation, or after being dried isomerized glucose syrup (where some and mixed with other types of forages of the glucose has been converted into such as maize stalks or rice hulls (CIP, fructose to sweeten it further). 1991).
In Japan and Korea, starches and Peru. The prospects for starch other fermentable carbohydrates are extraction in Peru are good, especially used to distil a typical liquor called in rural agroindustry, as are potato and socchu. Lactic acid, acetone, butanol, maize starches, both widely used in the vinegar, and leavenings are also country. Sweetpotato starch could be produced by fermentative processes. used in the food, textile, glue, paint, and cardboard industries. A company has Japan has developed a cyclodextrin begun manufacturing starch extraction with diverse, high-value uses in the equipment adapted to small- and food and pharmaceutical industries medium-scale farming conditions. and in blood tests. CIP’s Plant Breeding Program has China. Sichuan Province is the developed advanced clones, with world’s largest producer of adequate processing characteristics, sweetpotato, most of which is used in that are undergoing final testing and processed products and animal feeds. selection for release by the Instituto The crop forms the major source of Nacional de Investigación Agraria (INIA). income for most of the inhabitants. The clones should have high dry-matter Simple, small-scale technology is used content, high yields, low oxidation rate, to produce starch and noodles. The low fiber content, and very low latex noodles are similar to the rice noodles content (Table 4).
Table 4. Preliminary data of clones selected for starch contenta and suitable for industrial processing, Peru.
Clone Color Dry matter Starch (%) (%)
SR 87.070 White 37.6 25.83 SR 90.012 Cream 38.6 23.66 SR 90.021 Cream 30.0 20.30 SR 90.323 Orange 42.8 22.80 YM 89.240 White 35.2 23.41 YM 89.052 White 29.8 20.47 a. Analyses carried out by Derivados del Maíz, S. A. (DEMSA).
75 Cassava Flour and Starch: Progress in Research and Development
INIA is also assessing about (12) Sweetpotato pastes with high 1,000 clones for human β-carotene content for baby consumption, processing, and foods. forage purposes in the Cañete region. A private company has evaluated 42 of these clones for Conclusions dry-matter and starch contents. Six clones had high yields, and high The potential of sweetpotato dry-matter and starch contents, processing will be realized if: indicating broad potential for further research (Table 4). (1) Sweetpotato breeding is directed toward processing. This means using the world collection of Agroindustrial Prospects germplasm and installing facilities for conducting The following list summarizes the production trials at different agroindustrial prospects of sites. sweetpotato: (2) Collaborative research projects are conducted to develop new (1) Grated, raw sweetpotato for products. preparing an economic bread. (3) Information on experiences in (2) Sun-dried flakes for producing other countries is collected and starch, alcohol, or flour for organized to help design human consumption, animal strategies and policies that feed, and industry. would support sweetpotato (3) Sweetpotato flour for processing. preparing porridge, breads, (4) The private sector participates biscuits, and balanced feeds actively. Links must therefore for poultry and swine be established with the private (replacing maize). sector. (4) Sweetpotato starch for preparing noodles and glucose syrup (dextrins). Peru imports References glucose to produce pharmaceutical syrups, Achata, A.; Fano, H.; Goyas, H.; Chiang, O.; caramels, and gum drops. It and Andrade, M. 1990. El camote is also used by the textile and (batata) en el sistema alimentario del Perú: El caso del Valle de Cañete. glue industries. Centro Internacional de la Papa (CIP), (5) Production of alcohol (Japan, Lima, Peru. 63 p. Korea). (6) Sweets (e.g., flakes and Berrios, D. and Beavogui, M. 1992. Trials for the introduction of sweetpotato in caramels). breadmaking in Burundi. In: Scott, (7) Ketchup (Philippines). G. J.; Ferguson, P. I.; and Herrera, (8) Fruit-flavored juices J. E. (eds.). Product development for (Philippines). root and tuber crops, vol. III—Africa: (9) Liquor (Japan, Korea). proceedings of an international meeting held 26 October-2 November, (10) Balanced feeds for poultry and 1991, at IITA, Ibadan, Nigeria. Centro swine (replacing maize). Internacional de la Papa (CIP), Lima, (11) Extracting anthocyanin, a Peru. 506 p. natural purple coloring used CIP (Centro Internacional de la Papa). in preparing ice cream, yogurt, 1991. Informe anual. Lima, Peru. and pastries. 258 p.
76 Sweetpotato Flour and Starch:...
Denen, H.; Espínola, N.; Galarreta, V.; Herrera, Scott, G. J. 1992. Transformación de los J.; and Sluimer, P. 1993. Actividades cultivos alimenticios tradicionales: propuestas para el crecimiento de la Desarrollo de productos a base de producción de camote mediante la raíces y tubérculos. In: Desarrollo de ampliación de su utilización: Informe de productos de raíces y tubérculos, la misión para formular proyectos de vol. II—América Latina: proceedings desarrollo de productos de camote of an international meeting held realizada del 10 al 21 de mayo de 1993, 8-12 April, 1991, at the Instituto de por encargo de la Embajada Real de los Ciencia y Tecnología Agrícolas (ICTA), Países Bajos, en colaboración con la Villa Nueva, Guatemala. Centro Secretaría Ejecutiva de Cooperación Internacional de la Papa (CIP), Lima, Internacional del Ministerio de la Peru. 375 p. Presidencia (SECTI/MIPRE), bajo la coordinación del Centro Internacional Timmins, W. H.; Marter, A. D.; Wesby, A.; de la Papa (CIP), Lima, Peru. 79 p. and Rickard, J. E. 1992. Aspects of (Typescript.) sweetpotato processing in Sichuan Province, People’s Republic of China. Espínola, N. 1992. Alimentación animal con In: Product Development for Root and batata (Ipomoea batatas) en Tuber Crops, vol. 1—Asia: Latinoamérica. Turrialba proceedings of an international 42(1):114-126. meeting held 22 April-1 May, 1991, at the Visayas State College of Peralta, P.; Cavero, W.; and Chumbe, V. 1992. Agriculture (ViSCA), Baybay, Leyte, Un diagnóstico rápido del pan de Philippines. Centro Internacional de camote en el Perú. In: Desarrollo de la Papa (CIP), Lima, Peru. 384 p. productos de raíces y tubérculos en América Latina, vol. II—América Latina: Vásquez, H. 1994. Procesamiento a bajo proceedings of an international meeting costo de la harina de camote. Paper held 8-12 April, 1991, at the Instituto presented at the second meeting de Ciencia y Tecnología Agrícolas of the Grupo de Camote, held (ICTA), Villa Nueva, Guatemala. Centro 7 January, 1994. Centro Internacional de la Papa (CIP), Lima, Internacional de la Papa (CIP), Lima, Peru. 375 p. Peru. (Typescript.)
Ruiz, M. E.; Pezo, D.; and Martínez, L. 1980. Woolfe, J. 1992. The sweet potato, an The use of sweetpotato (Ipomoea untapped food resource. Cambridge batatas (L.) Lam) in animal feeding. University Press, Cambridge, UK. Trop. Anim. Prod. 5:144-151. 643 p.
77 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 11
PROSPECTS FOR CASSAVA STARCH IN VIETNAM1
Dang Thanh Ha*, Le Cong Tru*, and G. Henry**
Introduction analyzing constraints and opportunities for the cassava sector. As the third most important crop after The 1991 cassava benchmark study rice and maize, cassava accounts for (Howeler, 1996) included household 30% to 40% of secondary food surveys, focusing on cassava production in Vietnam (Thang, 1993). production, on-farm processing, use The total production of cassava was and consumption, and rural, 2.47 million tons of fresh roots in semiurban, and urban marketing. 1992 (Statistical Yearbook of Also included were processing Vietnam, 1993) planted on surveys, which focused on the 277,200 ha. The Vietnamese technical and socioeconomic aspects Government has shown interest in of different products processed and this root crop as a cheap raw material major marketing channels. for further processing. Results from an analysis In 1989, the Vietnamese Root and conducted by Henry et al. (1993) on Tuber Research Program was founded the main constraints to cassava as the first step toward strategically production, productivity, processing, reorganizing root crop research in and marketing could serve as a base Vietnam. In the past, most efforts in for strategic research planning in agricultural research and Vietnam. Cassava-based products development in Vietnam concentrated seem potentially significant for the on production and little is known future. Henry et al. (1993) also about consumer and user needs. reviewed the products and market From 1990 onward, with CIAT’s opportunities of cassava in Vietnam, assistance, a series of cassava but data were scarce and information production, processing, and incomplete. marketing analyses were conducted in Vietnam, aimed at identifying and For decisions on future cassava research and development in Vietnam, additional in-depth studies are required to analyze current and future potential demand of different * Department of Agricultural Economics, cassava-based products. Research on University of Agriculture and Forestry, market demand is important because Thuduc, Ho Chi Minh City, Vietnam. consumer needs (including industry, ** Cassava Program, CIAT, Cali, Colombia. on-farm use, etc.) should first be 1. No abstract was provided by the authors. assessed and then production,
78 Prospects for Cassava Starch in Vietnam processing, and marketing technology Current Cassava Use geared to address specific opportunities. Cassava roots have been used for different purposes such as animal This study aims, first, to analyze feed (flour), starch production (wet current use of, and relative quantities and dry starch), fresh roots for of, starch for different end products; human consumption, dried chips for second, to estimate starch demand of export, and home-processing these products for the future; and purposes such as maltose and alcohol third, to recommend issues for future (Table 1). cassava research and development activities. Fresh roots (for human consumption) and flour for animal feed (both at the farm and by Methodology industry) account for about 73% of the total cassava production in Data were collected by interviewing Vietnam. Total production of pigs processors, traders, personnel from was about 13.9 million head and of export companies, and manufacturers poultry, about 124.5 million head, who use cassava starch as a raw representing the use of about material. With manufacturers, the 1.4 million tons of cassava roots. interview format included questions Cassava starch production is the on production level, current inclusion second source of root consumption, ratio of cassava starch, production representing about 16% of total technology, technical requirements production. Chips for export account for cassava starch, its growth rate, for almost 5%, and home-processing and future demand. The time series (not including dried chips) 6%. data available on cassava starch consumption for each end product Currently, dried cassava starch is and for the manufacture of some used in food processing and for home products are neither reliable nor consumption, exported, and used by consistent. Future cassava starch several industries such as textiles, demand was therefore estimated by pharmaceuticals, cardboard, using a simple method based on monosodium glutamate (MSG), population and income growth. glucose, maltose, and plywood. The
Table 1. Cassava consumption in Vietnam, 1992.
Use Quantity of fresh roots
(t) (%)
Fresh roots (human consumption) 301,376.60 12 Animal feed (by farmers and industry) 1,503,845.90 61 Dried chips for export 120,000.00 5
Starch production: Dried starch (80%) 316,062.00 Wet starch (20%) 79,015.50 Total starch (100%) 395,077.50 16
Home processing (dried chips and starch not included) 150,000.00 6 Total 2,470,300.00 100
79 Cassava Flour and Starch: Progress in Research and Development total demand for cassava roots for rates), limited and fluctuating root starch production (both wet and supplies, seasonality, restricted dried) was about 395,077 t in 1992. capital, and poor market About 20% went to wet starch organization. These lead to low production, mostly for local profits and fluctuating quality and processing into low quality noodles levels of supply. Some large (Binh et al., 1992). processing plants also use old technologies. Currently, investors are interested in improving cassava Cassava Starch Processing starch processing technologies. and Marketing
During the Vietnamese cassava Current Use of Cassava benchmark survey in 1991, cassava Starch in Vietnamese starch processing was found to be Industry practiced in most of the provinces surveyed. But the largest cassava Table 2 summarizes current cassava starch processing areas are in the starch use. Most dried starch is provinces of Dongnai and Tayninh, consumed at home (about 57%) and and Ho Chi Minh City. Cassava by food processing industries (about starch is produced either dried (about 36%). 80% of the total starch production) or wet (20%) (Binh et al., 1992). Food processing and home consumption Most cassava starch production is conducted by the household or Households form the largest group of village. It is constrained by consumers of cassava roots (about traditional technology (low conversion 60,000 t/year). Cassava starch is
Table 2. Use and quantity of starch in different end products, 1992, and potential demand of cassava by year 2000.
End product Starch Potential demand in year 2000 consumption (t) (%) (t) (%)
Dried starch Food processing 25,000 35.60 30,000 16.51 Home consumption 40,000 56.95 45,000 24.76 Textiles 1,550 2.21 2,000 1.10 Monosodium glutamate 0 0 90,000 49.53 Carton 600 0.85 1,200 0.66 Glue (other purposes) 50 0.07 150 0.08 Plywood 96 0.14 120 0.07 Maltose 40 0.06 100 0.06 Glucose 1,800 2.56 3,000 1.65 Pharmaceutical products 100 0.14 150 0.08 Exports 1,000 1.42 10,000 5.50 Total 70,236 100.00 181,720 100.00
Wet starch (Cakes, noodles, etc.) 17,559 18,000
Total starch consumption 87,795 199,720
Fresh root consumption 395,077 898,740
80 Prospects for Cassava Starch in Vietnam used to bake cakes, fry meat and fish, The low conversion rates, poor make soup, and cook other traditional product quality, and high production Vietnamese dishes. Cassava starch is costs made local MSG unable to bought from retailers, who obtain it compete with imported MSG. Thus, from wholesalers in urban and local many companies ceased production markets, who, in their turn, receive it or attempted to modernize their from processing centers. technology, sometimes through joint ventures with foreign partners. The The food processing industry, production of MSG decreased from currently the country’s second largest 2,003 t in 1987 to 721 t in 1992 consumer, uses about 25,000 t of (Statistical Yearbook of Vietnam, high quality dried cassava starch per 1993). In 1987, almost 12,000 t of year. A diverse range of products is cassava starch were used by this made, including bread, rice chips, industry. But with modern and cakes. About 30% of total starch technology, MSG is produced mostly used in rice chips is cassava. For from imported glutamate azide and making cakes, cassava starch is not from cassava starch. mixed with other starches from soybean, green bean, rice, and wheat Since 1990, several foreign flours. To be competitive with other multinationals have entered the MSG starches, cassava starch must be sector. At first, they imported MSG to cheap and of high quality. sell in Vietnam, but after conducting market research, they concluded that Monosodium glutamate production producing MSG in Vietnam was a viable option. Currently, they are The total MSG used in Vietnam is producing MSG from glutamate azide currently about 40,000 t/year. Most imported from the mother company. is imported from Japan, Taiwan, and At the same time, they are Singapore, with only a small amount researching the market potential of produced nationally. In the 1980s, MSG produced from local raw Vietnamese companies produced material, availability of raw materials MSG, using as raw material either (cassava starch, byproducts from the cassava starch (75%) or byproducts sugar industry, and other starch from the sugar industry (25%). These sources), possible sites, and companies used old technology with production organization. Four new low conversion rates: 6-6.5 t of MSG factories, with a capacity of cassava starch produced 1 t of MSG. 35-40 thousand tons/year, are now being planned. Cassava starch was obtained from processing centers through Textile industry wholesalers. A starch quality of 90%-92% purity was required. About 1,550 t of cassava starch are Constraints included fluctuating currently used per year by the textile starch quality as a result of industry as size for weaving cotton processors using different fabrics. Other possible substitute technologies; and erratic supplies starches are maize, wheat flour, because root availability depended on potato, and rice. In the past, some harvest seasons. The MSG textile factories in northern Vietnam companies had to store starch, but used maize starch, which was more often lacked good storage facilities, readily available in the Red River which, with the starch’s variable Delta than cassava starch. Later, as consistency and low quality, caused supplies increased, most factories quality losses. changed to cassava starch, which is
81 Cassava Flour and Starch: Progress in Research and Development technically more suitable and also About 200 kg of cassava starch cheaper. The Government also are needed to produce 5 t of encouraged the industry to replace cardboard. Currently, about 600 t of starches from other food crops with cassava starch are used to produce that from cassava. an annual 15,000 t of carton.
Starch supplies arrive at the The estimated consumption of factories from the processing centers cassava starch for glues for other through wholesalers. The average purposes, such as for offices and price of high quality cassava starch, packing materials, is about 50 t/year. in Vietnamese dôngs (VND), is about VND 2,000 to VND 2,200/kg. Starch Maltose and glucose production for the textile industry must be homogeneous in quality, pure Maltose production in Vietnam (92%-95%), highly adhesive, consumes about 40 t of cassava white—with no change in starch annually, and that of glucose color—unfermented, and resistant about 1,800 t. To produce 1 t of to quality loss when stored. maltose, about 1-1.5 t of cassava starch is needed, and for 1 t of Some textile factories use modern glucose syrup, about 300 kg.2 Starch weaving machinery that has a high has to be at least 90% pure for these production capacity and high weaving two products. Maltose and glucose speed. Such machinery requires high are used by the pharmaceutical and quality glue, which is imported. This food-processing industries, which glue could be made from chemically thus govern demand. modified cassava starch, a product that is likely to be used by the textile Plywood industry industry in the future. But raw cassava starch will still be used in Together with urea, formaldehyde, small weaving factories, and for and other chemicals, cassava starch producing the currently imported is used to produce industrial glue for glue. plywood production. To produce 1 m2 of plywood, 0.46 kg of industrial glue Glues for cardboard production and is used, of which about 30%-35% is other purposes cassava starch. Wheat flour could also be used, but, because of its To produce cardboard and other relatively low price, cassava starch is packing materials, starch from preferred. Starch must be pure (less wheat flour, maize, rice, and than 5% of substance remaining after cassava is used as glue. In burning), with a pH value of 5.5 to 6 Vietnam, cassava starch and flour (in unfermented starch), and contain are readily available and relatively less than 10% cellulose. Whiteness is cheap. Small cardboard-producing not important. Current plywood units with simple technology use production is about 700,000 m2, both cassava flour and starch, but consuming about 96 t of cassava large modern factories use only starch annually. cassava starch, as the flour does not reach technical standards. Cassava starch must be highly adhesive and pure (90%-92%). 2. Glucose syrup is a concentrated aqueous solution of saccharides derived from the Whiteness is not so important. original starch. Hence, a greater weight of Most processing centers can satisfy syrup is obtained from a given weight of these criteria. starch.
82 Prospects for Cassava Starch in Vietnam
The proportion of cassava starch of cassava starch urgently needs in glues for plywood is relatively high improving to produce high quality in Vietnam. In the 1980s, the cost of dextrin, maltose dextrin, and glucose glues was about 30%-35% of total for pharmaceutical use. production costs. Producers therefore reduced production costs by including Exports high rates of cassava starch (35%), which decreased the product’s Vietnam exports mostly dried cassava quality. As chemicals for glue chips and only a small quantity of manufacture became cheaper, the dried cassava starch. About 30,000 t proportion of cassava starch dropped of cassava chips is exported annually from 35% to 30%. to the European Union (EU), 10,000 t to Asian countries, and only 1,000 t Pharmaceutical industry of cassava starch and tapioca pearl to neighboring countries. Cassava chips At present, the pharmaceutical exported to the EU cost US$120 to industry uses cassava starch to US$130/t, whereas chips to Asian produce medicinal tablets and pills. countries cost US$70 to US$80/t. Purity, whiteness, and adhesiveness Because of the higher prices of are the most important criteria, which exports to the EU, the local price of traditional technology usually does dried chips has increased and exports not meet. Thus, starch bought from to Asian countries have dropped. processing centers has to undergo Asian export companies have further processing to reach the therefore changed to exporting needed quality. About 100 t of cassava starch or tapioca pearl. cassava starch is consumed annually by this industry. Major constraints to cassava starch export, however, are poor Despite the extra processing starch quality, inefficient processing needed, cassava starch is cheaper and marketing system, shortages or than other starches such as rice or poor storage facilities, relatively high potato, and is in plentiful supply. transport costs, and insufficient The technology for using cassava supplies. The current conversion starch is also more readily rate from fresh root to dried starch available. in processing is 5:1 in the wet season and 4:1 in the dry season. One constraint is that, under Dry matter content is high in the dry some circumstances, the season but farmers set their adhesiveness of dried cassava starch cropping calendar so that they can is not as good as that of other harvest in the wet season when less starches. For example, in the labor is needed, but when both processing of certain medicines, water starch content and conversion rates cannot be used because it may are low and the high humidity interfere with the medicine’s effects. makes drying the starch difficult. Research is therefore needed on Many processors therefore cannot technologies that can directly use produce export quality starch. The dried cassava starch in producing small-scale processing and low tablets and pills. starch quality make collecting enough starch for export difficult. Although cassava processing These constraints make Vietnamese factories specializing in starch for cassava starch noncompetitive with pharmaceutical use satisfy the starch from China and Thailand. industry’s requirements, the quality
83 Cassava Flour and Starch: Progress in Research and Development
Although labor is cheap and for cassava starch is high, even with farmgate prices are low in Vietnam, byproducts from the sugar industry Thailand has more advantages for as an alternative source of starch. producing cassava starch. These are Modern technology and suitable lower prices for fresh roots (farmgate bacteria will help increase the price is about US$20/t), large-scale conversion rate from cassava starch and highly efficient processing, a very to MSG. Despite the increased use of efficient marketing system with good byproducts from the sugar industry storage facilities, high starch quality, (because of their lower prices), the large volumes, and low transport demand for cassava starch will still be costs. high, probably at about 90,000 t/year in the year 2000. Nevertheless, foreign companies with high production capacity, better However, some constraints technology, and better export facilities operate against using cassava starch have invested in cassava starch in this industry, one of which is the production in Vietnam. These large volumes of starch needed daily investments may generate an as raw material. For example, to increased opportunity for cassava produce 10,000 t of MSG per year, a starch exports in the future. company needs about 29 t of cassava starch of 90% purity per day. About 116 t of fresh roots per Cassava Starch Market day are needed to produce this Potential amount of starch. Hence, obtaining sufficient supplies under current Future domestic demand for conditions is difficult. Even different end products collecting such large volumes is costly, especially in areas where Cassava starch consumption is cassava production is not currently important, accounting for concentrated. Transport costs are about 20% of the total cassava acceptable up to a distance of production. Assessments of the 120 km around the plant, but stability of this status revealed organizing the collection can be a considerable future potential, with problem. increasing demand from the MSG and other food processing industries, and Another problem is the seasonal household consumption. nature of harvesting cassava, occupying about 5 to 6 months/year, The demand for MSG is expected coupled with a lack of adequate to grow to 60,000 t by the year 2000. storage facilities. Hence, supplies of Although MSG production for starch for year-round production are domestic consumption is growing, insufficient. increasing production for export is difficult because neighboring If these constraints could be countries also produce MSG, and in resolved, then the demand for sufficient quantities for their own cassava starch for MSG production consumption. MSG production in would be high. Vietnam therefore satisfies mostly domestic demand. Cassava starch, as a food for household consumption, is inferior Currently, most companies are and its demand declines with increase using imported glutamate azide to in consumer income. However, produce the MSG, but the potential demand grows with population
84 Prospects for Cassava Starch in Vietnam increase. With an expected pharmaceutical industry will not population growth of 2.1% and an increase much. The demand in expected gross national product (GNP) glucose production may be higher growth of 8%/year, the demand for with about 3,000 t/year. Table 2 cassava starch for household summarizes the estimated future consumption, is conservatively demand by industry. estimated to increase from 60,000 to 65,000 t/year by the year 2000. Export potential
In the food processing industry, By the year 2000, cassava starch as products diversify, the use of exports will have significantly cassava starch will increase greatly in increased. At present, foreign the future. Cassava starch will be companies are investing in the used in producing higher quality food cassava processing sector and products and new ones such as exporting their products. The different kinds of cakes and snacks. prospects for increased exports of But higher starch quality will be cassava starch are good, once large needed. processing plants are at full capacity and using modern technology. Better Textile industries are expected to facilities and high-yielding varieties expand substantially. Thus, with high starch content would demand for high quality glues (made improve the conversion ratio and from chemically modified starch) starch quality, and lower production and modern technology, such as costs. By the year 2000, export high-speed weaving machinery, will volume may reach 10,000 t/year. increase demand for modified But once the comparative advantage cassava starch, which, in turn, may of cheap labor declines, more starch encourage the local production of will be used for domestic industrial cassava starch. The potential consumption. demand for cassava starch in the textile industry is expected to be Competition from other starches about 2,000 t/year. Cassava starch has a relatively lower Demand for cassava starch as price than rice starch and wheat flour raw material for glues for cardboard (Table 3), a price relationship which is production is expected to increase to about 1,200 t and for other purposes to 150 t. These demands, however, account for only a small Table 3. Prices of some products in Ho Chi Minh proportion of the total future starch City, Vietnam, November 1993. (VND 1,080.00 = US$1.00.) demand. Product Wholesale price Retail price In the plywood industry, higher (VND/kg) (VND/kg) quality plywood will be needed. The Cassava starch quality: proportion of cassava starch as raw I 2,200 2,300 material for glue production will II 2,000 2,200 decline from 30% to 20%-25% in the III 1,800 2,000 future. But if plywood production Rice starch 2,900 3,000 increases, about 120 t of cassava Wheat flour 3,000 3,200 will be used annually. Cassava flour 950 1,300 Cassava noodles 3,200 3,300 The demand for cassava starch for Monosodium glutamate 5,500 16,000 maltose production and for the
85 Cassava Flour and Starch: Progress in Research and Development unlikely to change in the future. The food processing, household price of rice starch will not decline consumption, textiles, and glucose compared with that of cassava are the current major cassava starch starch because of technology and consumers. Demand in the MSG because the Government will not industry is expected to increase encourage the use of rice starch in greatly. Little change will occur in industry. Wheat flour is less the demand for cassava starch in food competitive with industrial cassava processing and household starch because it is imported, thus consumption, which is expected to using scarce currency and increasing remain very high in these two sectors. production costs. Other starches In the food processing industry, such as cinnamon and maize are products using cassava starch are mostly used in the food processing highly diverse, requiring better starch sector, being either too expensive or quality. Cassava starch exports will too scarce for industrial use. also increase substantially. Demand for cassava starch by the year 2000 is The influence of government expected to be more than twice the policies on market potential present level (Table 4).
The Vietnamese Government The trend of cultivated areas in emphasizes substitution by cassava Vietnam (Table 5) shows that the area and other roots and tubers to favor planted to cassava is decreasing and rice for domestic human productivity is only slightly consumption and export. The increasing. In the future, the cassava Government also encourages the area is likely to decrease further as export of agricultural products, other industrial crops of higher value including cassava-based products, replace cassava. With the expected such as dried chips and starch, increase in future demand for cassava through a zero export tax. Taxes are starch, a gap between supply and also used to protect domestic demand will develop. The gap will production by limiting the import of widen further with increasing goods that can be produced in demand for cassava flour for livestock Vietnam. For example, the import and poultry feed. If cassava tax on MSG and wheat flour is 20% productivity is not improved, of the c.i.f. (cost, insurance, and shortages can be expected in the freight) price. future.
The Government policy also Because cassava area cannot be encourages investment in the increased, extra supplies can be cassava sector. These policies can obtained only by intensifying cassava greatly affect the business potential production. Introducing high-yielding of cassava starch, especially in the and high starch content varieties MSG industry and cassava would help solve this problem. processing for export. As a result, several foreign companies have But introducing high-yielding invested in these two sectors. varieties requires research on adopting new varieties in different agronomic regions, transferring Conclusions technology to farmers, and the farmers’ adopting new technology. The analysis of current cassava Despite the higher yields, improved starch use and proportion of starch varieties require much more chemical in different end products reveals that fertilizers, pesticides, and labor than
86 Prospects for Cassava Starch in Vietnam
Table 4. Potential growth of cassava starch by industry, Vietnam, 1992-2000.
Product 1992 demand Estimated demand Growth rate (t) in year 2000 (t) (%)
Dried starch Food processing 25,000 30,000 20 Home consumption 40,000 45,000 13 Textiles 1,550 2,000 29 Monosodium glutamate 0 90,000 very large Carton 600 1,200 100 Glue for other purposes 50 150 200 Plywood 96 120 25 Maltose 40 100 150 Glucose 1,800 3,000 67 Pharmaceutical products 100 150 50 Exports 1,000 10,000 900
Total 70,236 181,720 159
Wet starch 17,559 18,000 3
Total starch consumption 87,795 199,720 127
Total fresh root consumption 395,077 898,740 127
Table 5. Total cultivated area and production of disposition toward cassava-based cassava in Vietnam, 1976-1992. products created. Such integrated Year Cultivated area Production research needs cooperation among (000 ha) (000 t) agronomists, plant breeders, processing technologists, and 1976 243.5 1,843.1 economists. Only by these means can 1980 442.9 3,323.0 possible losses to society be 1985 335.0 2,939.8 eliminated. For example, in 1987, 1986 314.7 2,882.3 farmers were encouraged to produce 1987 298.9 2,738.3 1988 317.7 2,838.3 more cassava even though market 1989 284.6 2,585.4 demand was decreasing. The result 1990 256.8 2,275.8 was an over supply of cassava and a 1991 273.2 2,454.9 significant drop in the price of fresh 1992 277.2 2,470.3 roots. The drop was so great that farmers did not harvest. SOURCE: Statistical Year Book of Vietnam, 1993. To develop the cassava sector, the Government should provide adequate do local varieties, and not all farmers statistics and make information on can afford them. Ignorance of new prices, demand, and other marketing technology and lack of credit are features widely available to help further constraints to farmers’ farmers, processors, and other adopting new technology, requiring producers decide appropriately. The increased extension. Government should also clearly indicate its pricing policies. For the cassava sector and agriculture in general to develop in The technical requirements of harmony, cassava production, starch quantity and the quality of processing, and marketing must be different end products made with coordinated, and a favorable cassava starch could be used as
87 Cassava Flour and Starch: Progress in Research and Development criteria for cassava production and Howeler, R. H. (ed.). 1996. A benchmark starch processing. To satisfy future study on cassava production, requirements for cassava starch processing and marketing in Vietnam: proceedings of a workshop quantity and quality, many held in Hanoi, Vietnam, Oct. 29-31, improvements in production, 1992, to present and discuss the processing, and marketing should be results of a nation-wide survey made. Traditional processing units conducted in 1991-1992. Vietnam must invest in modern processing Ministry of Agriculture and Food Industry (MAFI) and Regional plant and improve their efficiency, Cassava Program for Asia, CIAT, that is, have higher conversion ratios Bangkok, Thailand. 284 p. and better starch quality. Thang, N. V. 1993. Cassava in Vietnam: an overview. Draft for: Howeler, R. H. (ed.). A benchmark study on cassava References production, processing and marketing in Vietnam: proceedings of Binh, P. T.; Hung, N. M.; Tru, L. C.; and a workshop held in Hanoi, Vietnam, Henry, G. 1993. Socio-economic Oct. 29-31, 1992, to present and aspects of cassava production, discuss the results of a nation-wide marketing and rural processing in survey conducted in 1991-1992. Vietnam. Draft for: Howeler, R. H. Vietnam Ministry of Agriculture and (ed.). A benchmark study on cassava Food Industry (MAFI) and Regional production, processing and Cassava Program for Asia, CIAT, marketing in Vietnam: proceedings of Bangkok, Thailand. p. 12-33. a workshop held in Hanoi, Vietnam, Oct. 29-31, 1992, to present and Statistical Year Book of Vietnam. 1993. discuss the results of a nation-wide Hanoi, Vietnam. survey conducted in 1991-1992. Vietnam Ministry of Agriculture and Food Industry (MAFI) and Regional Cassava Program for Asia, CIAT, Bangkok, Thailand. p. 113-158.
Henry, G.; Binh, P. T.; Tru, L. C.; and Gottret, M. V. 1993. Cassava constraints and opportunities in Vietnam: a step toward a common R&D agenda. Working document no. 128. CIAT, Cali, Colombia.
88 Cassava Flour Processing and Marketing in Indonesia
CHAPTER 12
CASSAVA FLOUR PROCESSING AND MARKETING IN INDONESIA
D. S. Damardjati*, S. Widowati*, T. Bottema**, and G. Henry***
Abstract Small farmers and farmer groups receive increased added value by In Indonesia, cassava is the fourth producing cassava chiplets (sawut) most important food crop after rice, instead of gaplek (dried cassava maize, and soybeans. An average of chips). Marketing, however, is still a 16 million tons of cassava is produced major constraint for the cassava flour annually, most of which goes to starch agroindustry. extraction or is exported as pellets and chips. But markets are unstable and A consumer-acceptance study, farmers have few incentives to produce conducted in the Purwakarta region more cassava. and Ponorogo district, showed that about 80% of cassava flour was Processing for cassava flour began considered acceptable. About 84% of in 1990 to diversify cassava products. consumers thought the flour was The cassava flour agroindustry acceptable for household consists of three major production consumption, which was estimated at systems: at the farm (model 1), 4-7 kg/month per household. farmers’ groups (model 2), and the mill, Because cassava flour can substitute which acts as a nucleus by linking wheat flour in wheat-based products farmers and farmers’ groups, through by as much as 30%, the entire local their fresh roots and dried chips, with production of cassava flour can be cassava flour distributors and absorbed, especially by the food consumers (model 3). Processing industries. PT Mariza, a private capacities of the three systems during company, has begun industrial harvesting are about 75 kg of roots per production of cassava flour and is day for model 1, 500 kg for model 2, developing a marketing system. and 10,000 kg for model 3. Yield recovery of 25% to 30% has been obtained for dried chips, and 24% to Introduction 29% for cassava flour. Agriculture is an important component of the Indonesian economy, providing 49% of total * Bogor Research Institute for Food Crops (BORIF), Bogor, Indonesia employment, and about 18% of the ** Center for Research and Development of gross domestic product (GDP). Food Coarse Grains, Pulses, Roots and Tuber crops alone represent 62% of the GDP Crops in the Humid Tropics of Asia and the Pacific (CGPRT), Bogor, Indonesia from the agricultural sector, that is, *** Cassava Program, CIAT, Cali, Colombia. 12% of the total GDP (1991 figures).
89 Cassava Flour and Starch: Progress in Research and Development
Rice is the chief food crop, followed cassava-growing regions have by soybeans, maize, and cassava. increased. (Less than 10 years ago Other secondary crops are peanuts, about 65% of total production came mung beans, and sweetpotatoes. from Java alone [Dimyati and Minor crops with a potential future in Manwan, 1992]). Factors causing the food production are several cereals, reduced harvest area are complex: legumes, roots, and tubers. incentives and sharp price fluctuations have induced farmers to Cassava is grown on about grow cassava, but factors such as 1.4 million hectares throughout the establishing irrigation facilities and country, with an average production of reforestation have reduced planting 16.3 million tons/year (CBS, 1992). area. The crop is used as food and for starch extraction, and is exported as The average yield per hectare of feed (Damardjati et al., 1992). The cassava is rather low at 12 t, but the cassava market overall, however, is trend has been toward a constant unstable and tends to discourage increase in yields. A much higher farmers from producing cassava. yield can be obtained through improved cultural practices. On the Recently, the Government began estate of a tapioca plant in Lampung, promoting cassava for industrial a yield of 25-30 t/ha of cassava has purposes and food. A preliminary been continuously attained economic analysis indicated that (Rusastra, 1988) as a result of a cassava flour production and use in cassava intensification program processed foods would be feasible. A started by the Government in 1975 series of investigations on cassava (Dimyati and Manwan, 1992). flour production and use was therefore Moreover, research findings suggest begun by several research institutes that yields can be as much as operating under the auspices of the 75 t/ha. Central Research Institute for Food Crops (CRIFC). Between 1978 and 1992, cassava production fluctuated, with a peak at The CRIFC then collaborated with 17.1 million tons during the late private companies to develop a 1980s. In 1992, about 16 million tons cassava-flour agroindustry model at were produced (Figure 1). the village level in several locations in Indonesia (Damardjati et al., 1992).
This paper presents the results of 30 our study on the development of the cassava-flour production system, 25 consumer acceptance, and the 20 marketing of cassava flour. 15
10 Cassava Production, Consumption, and Use Supply (million tons) 5 0 Production 1978 80 82 84 86 88 90 92 Year In Indonesia during the past decade, Figure 1. Domestic supply of rice ( ), cassava ( ), the harvest area has decreased while and wheat ( ) in Indonesia, 1978-1992. both productivity and the number of (Taken from CBS, 1978-1992.)
90 Cassava Flour Processing and Marketing in Indonesia
Domestic demand and consumption Processing and use
Annual per capita consumption of According to the Indonesian food cassava as food has been decreasing balance sheet for 1991 (CBS, 1992), gradually from about 57 kg in 1983 to total cassava production in 1991 51 kg in 1988 (Damardjati et al., was almost 16 million tons. Of this, 1990). From 1988 to 1992, almost 57% was consumed as both consumption of cassava and other fresh and processed food, 21% was secondary crops fluctuated, showing a processed into gaplek and pellets, of correlation with rice consumption which 41% were exported and 59% (Table 1). went to industry. Tapioca starch was produced from about 8% of Cassava also became an important harvested cassava, mostly for export, export crop. Since 1982, Indonesia but, if sold on the domestic market, has exported a yearly quota of gaplek also for making krupuk. The rest is and pellets to the European Union used in other food, textile, paper, (EU), as well as to other countries. glucose, and pharmaceutical Since 1989, Indonesia has also industries. Postharvest losses are regularly exported tapioca starch still relatively high at 13% (Table 3). (Table 2). Cassava use in Indonesia differs Cassava availability for domestic throughout the country. In Java, food consumption is related to the where 60% of the population resides, total export of all cassava products cassava is primarily for human (chips, pellets, and starch). For consumption. Unnevhr (1990) example, domestic consumption of reported that the rural dwellers, cassava in 1990 was lower than that producers, and major consumers of in 1992, because exports were higher cassava use about 62% of roots and in 1990. 49% of the gaplek they produce for their family needs. The consumption of cassava as a foodstuff is concentrated in Java, thus Currently, the demand for making demand more stable and cassava in Indonesia seems to have easier to estimate. Outside Java, in reached a plateau, but experts areas such as Lampung, the anticipate an increase in domestic international market and industrial demand during the next decade for activities influence demand. both food and industrial purposes.
Table 1. Average per capita consumption of major food crops in Indonesia, 1986-1992.
Crop Consumption
1986 1988 1990 1992 kg/year cal/day kg/year cal/day kg/year cal/day kg/year cal/day
Rice 147.36 1,453 150.18 1,481 150.05 1,480 147.91 1,459 Cassava 51.44 154 51.00 154 43.07 129 57.40 172 Sweetpotato 11.05 32 10.93 32 9.74 28 10.34 30 Wheat 5.96 60 6.59 60 7.54 75 10.36 104 Maize 29.25 256 30.75 256 29.68 260 34.63 303 Soybean 8.80 80 9.45 80 10.72 97 12.57 114
SOURCES: CBS, 1988; 1990; 1992; 1994.
91 Cassava Flour and Starch: Progress in Research and Development
Table 2. International trade in Indonesian cassava (t), 1983-1992.
Year Exports Imports
Chips Starch Chips Starch
1983 358,346 1,602 - 63,883 1984 365,161 183 - 3 1985 343,303 107,000 - 21 1986 424,600 - 165,000 20,500 1987 783,776 116,000 41,750 9,500 1988 825,000 - 250,000 23,000 1989 834,000 282,000 - - 1990 697,000 487,000 - - 1991 494,000 317,000 - 12,000 1992 372,000 135,000 79,000 34,000
SOURCE: CBS, 1992.
Table 3. Trends of cassava production and use in Indonesia (thousands of tons).
Item Fresh cassavaa
1986 1988 1989 1990 1991 Percentageb of total production
Total production 13,312 15,471 17,117 15,830 15,954 100 Losses 1,572 2,011 2,225 2,058 2,074 13 Feed for domestic use 242 309 342 317 319 2 Roots for chips 4,281 3,900 3,336 21 Total chips produced (1,540) (1,403) (1,200) Exports (424) (825) (834) (697) (494) Tapioca starch 1,150 1,881 1,232 8 Domestic use (322) (527) (345) Exports (282) (487) (357) Food consumption 8,573 8,863 9,119 7,674 8,993 56 Food industry 5,431 5,781 4,568 a. Values in parentheses indicate dried cassava. b. Percentages are rounded.
SOURCES: CBS, 1988; 1990; 1991; 1992; 1993.
Developing of Appropriate The Indonesian Government is Technology for Cassava Flour attempting to develop the potential of cassava flour as a food for domestic Developing diversified uses for cassava consumption and as a raw material for and the appropriate technology should both household consumption and the extend the market and strengthen food industry to complement or farmers’ bargaining power in that they substitute wheat flour. The would have other buyers available and Government has recommended that could command better prices. New the agricultural and industrial sectors alternatives for cassava use should be make special efforts in promoting simple and easy, and give added value cassava by diversifying cassava directly to the farmers. processed products, improving their
92 Cassava Flour Processing and Marketing in Indonesia quality, and promoting their use sieved (Damardjati et al., 1992). The among the different strata of the village distribution and processing Indonesian population. system commonly used for handling agricultural products involves three Several research institutes, the types of processor groups: public sector, and private companies (1) individual farmers, (2) farmers’ have developed machine prototypes for groups, and (3) groups of village union cassava processing and new recipes for cooperatives, known as Koperasi Unit preparing food using cassava products, Desa (KUDs), processors, millers, and and have promoted the use of cassava flour producers. Figure 2 composite cassava-wheat flour in shows the overall cassava processing preparing foodstuffs such as breads, system, with three tradable products pasta, and cookies. produced during the processing of flour from harvesting to marketing: The use of a model of an (1) roots, (2) dried cassava chips, and agroindustrial system based on (3) cassava flour. cassava flour production would support efforts to transfer technology Models for cassava flour production from researchers to farmers, who could then commercialize the system. The The KUD or other entrepreneur group system would then be supported by a is appointed as the nucleus processor continuous distribution and marketing responsible for cassava-flour system. processing and marketing. Three models of cassava flour production can Developing the processing operation be derived from the overall pattern of cassava distribution and marketing To produce cassava flour, roots are and transaction products. The models peeled, washed, chipped, pressed, are individual farmers (model 1), dried, ground or milled, and then farmers’ groups (model 2), and cassava
Cassava Peeling Washing Chipping roots and soaking 1,000 kg
Pressing Slurry
Peel Drying Steeping 170 kg
Drying Chips Drying 330 kg
Feed Fiber Milling Starch 30 kg
Cassava Food flour industry 310 kg
Packaging
Figure 2. Model of cassava processing system in Indonesia. Ovals indicate tradable products.
93 Cassava Flour and Starch: Progress in Research and Development flour plants that act as nuclei that link (4) Sufficient infrastructure such as farmers and farmers’ groups, by buying transport and marketing facilities. their fresh roots and chips and milling them, with distributors and consumers Infrastructure needed to implement (model 3) (Damardjati et al., 1992). project
Implementing the project brought Developing the Agroindustry together all aspects of production, for Cassava Flour Processing processing, and marketing of cassava chips and flour. The most With finance from its own project appropriate available technology was budget, the ARM-AARD project, and tested in real-life situations. Table 4 the Government Corporation (PT Petro shows the space and installations Kimia Gresik), SURIF undertook to required for a village-level processing develop and establish a project to operation. develop a cassava-flour agroindustry for village farmers. PT Petro Kimia Problems encountered were Gresik acted as the nucleus company. variable product quality in farmer-processed chips; inadequate Site selection quality control for both chips and flour; inadequate communication Several sites were chosen for the between farmers and processors; project, based on the following criteria: difficulties in developing handling systems for poor quality chips; and (1) Desire to participate, and difficulties in establishing the social participation, on the part of organization needed for processes farmers (or farmers’ group) and the that produce marketable products. KUD or private company as Operational research directed toward processor in the production of resolving these problems was an dried chips and cassava flour. essential component of the project. (2) The village or subdistrict selected must be a cassava production Supply and sorting area. Fresh center at the district or provincial roots are supplied to this area and level. higher quality roots separated for (3) Readiness of the KUD or processor processing. This area is most to produce cassava flour and important at the processor level where collect dried chips from farmers or it is a part of the processing area. The their groups. roots are weighed, graded, grouped,
Table 4. Infrastructure required by three models of the cassava chip and flour agroindustry, Indonesia.
Infrastructure Model 1 Model 2 Model 3 (individual farmer) (farmers’ group) (processor as nucleus)
Supply and sorting area 4-8 10-16 20-30 (m²) Processing area (m²) 10-15 30-40 300-500 Drying area (m²) 20-30 80-100 800-1,000 Storage room for chips 8-12 20-30 200-300 (m²) Storage room for flour - - 1,000 (in tons of flour)
94 Cassava Flour Processing and Marketing in Indonesia and sequentially processed according the same as for chips. Cassava flour to their time of harvest. Ideally, all is more compact than chips, and roots should be processed no later therefore requires less space. Cassava than 24 h after harvest. flour is stored only for short periods before being sold. Processing area. In models 1 and 2, roots are peeled, washed, Processing procedures soaked, chipped, and pressed in this area. In model 3, milling and packing The procedures followed by the village are also done here. The area must plant to process cassava flour are root have a brick or plastered platform with handling, peeling, washing and sufficient slope to provide good soaking, chipping, pressing, drying, drainage and easy cleaning. In East milling, and packing. Java, the size of the processing area for model 3 is about 4 x 10 m. In model 1, Root handling. The processing is usually done in the characteristics and quality of the backyard or kitchen. Some model 2 eventual cassava products influence systems have an area set aside, the way roots are handled by farmers. usually in a group leader’s house or Root handling includes time and “office.” methods of harvesting, transport from the field, and storage. For a good Drying area. Sun drying is the quality product, roots should be most appropriate and cheapest method processed in less than 24 h after for all three models to dry chips. The harvest. drying area must be completely exposed to the sun, with a small Peeling. Roots are peeled shaded area where workers can spread manually with a knife or traditional wet chips on to trays before moving peeler, usually by women. Peeled them into the sun. The area is cassava yield is about 70%-80%, that completed with a wooden or bamboo is, 15-20 kg/ha per person. rack to hold the trays during drying. Ideally, trays are 0.8 x 2 m and can Washing and soaking. Peeled carry 7-10 kg of wet chips, depending cassava is washed thoroughly, then on the weather. Model 3 has a drying soaked overnight (for high-cyanogen area capacity of 6,000 kg. cultivars), or for a few minutes (low-cyanogen cultivars) while waiting Storage room for chips. Once to be chipped. Soaking should be done dried, chips are packed and stored in a in excess water to inhibit browning and room. The platformed floor is covered reduce cyanogenic (HCN) potential with wood or bamboo to protect the where necessary. chips from direct contact with the concrete or brick floor. In model 3, the Chipping and pressing. Peeled storage room is also used to keep and soaked roots are then chipped into products collected from farmers or 0.2-0.5 x 1-5 cm chips. The wet chips farmers’ groups. The chips are stored are then placed on a tray and pressed until milled or sold. In models 1 and with either a screw or hydraulic press. 2, no special area is set aside for Pressing reduces moisture, drying storing chips, which are stored with time, and HCN content, especially for other field produce in the central high-cyanogen cultivars. It is optional house. for low-cyanogen cultivars.
Storage room for flour. The floor Drying. Pressed chips are spread area for storing cassava flour is about out on a bamboo or aluminum tray,
95 Cassava Flour and Starch: Progress in Research and Development which is put on a rack in direct from other sources at a ratio of 60% to sunlight. Pressed chips take between 40%, respectively. These mixed chips 14 h and 2 days to dry, whereas are either suitably stored or milled for unpressed chips take 2-3 days. The distribution, or sent to the distributor. faster the drying, the better the quality of chips. This system has advantages for both the plant and the farmers. The Packing and milling. Dried plant guarantees that all chips chips are packed in double plastic produced by the farmers will be bags, which are tightly sealed. accepted and bought. Advantages for They can then be stored for about the plant are that its equipment, 6 months. Chips from models 1 and 2 especially the mill, operates at optimal are taken to the processor, whereas in capacity; it obtains, indirectly, drying model 3 the chips are milled to flour, areas from farmers and farmers’ using a 60-80 µm mesh. Usually the groups; labor efficiency is optimized; flour is packed into thick plastic bags and plant operational time is longer (0.5-1.0 kg) or into double sacks during the cassava off-season because (25 kg). of its stock of dried chips.
Implementing the agroindustrial Material, energy, and production model for cassava flour production cost analysis. Material conversion value in cassava flour processing is Processing operation system. influenced by root size and peel, The agroindustrial model follows a cassava variety, and equipment used. “foster-parent” system in which the Large, easily peeled roots mean higher big Government-owned corporations yields. Table 5 indicates the material are appointed as “foster parents.” The conversion in each processing step “foster-parent” company was (Damardjati et al., 1991). The average supported with equipment and yield of dried chips is 34% and of flour, technical skills through collaboration 32%. Screw pressing results in a with research and development slightly higher yield than hydraulic institutes. For example, pressing. The root cyanogenic potential SURIF/CRIFC and PT Petro Aneka strongly influences yield recovery of Usaha collaborated in founding an dried starch. Normally, high-cyanogen agroindustrial system for cassava flour cultivars contain more starch than do in Ponorogo district. low-cyanogen cultivars.
At the village level, an At the time of the study, labor agroindustrial model has been wages were 2,500 rupiahs/day developed in which the farmers or (exchange rate was Rp 2,126 = farmers’ groups produce dried chips US$1.00). Based on the as an intermediate product. The yield recovery of flour (32%), the total “foster parent” is the milling plant, production cost of cassava flour was which produces cassava flour. In this 18,725 rupiahs/kg. system, farmers produce dried chips two to three times a week, depending Economic analysis on their capacity and the weather. The farmers or farmers’ groups pool Price determination. Standard their dried chips before sending them prices are an important factor in the to the cassava flour plant. cassava flour agroindustry, and are usually higher than those of sliced The plant mixes the chips gaplek, which are unstable and depend collected from this source with those on middlemen. Farmers have no
96 Cassava Flour Processing and Marketing in Indonesia bargaining power. Gaplek prices and the “foster-parent” factory always decrease, especially during peak collaborated to determine a standard season. Farmers producing dried chips price for dried chips, which, in 1992, also face the same problem as do was 270 rupiahs/kg of chips. gaplek farmers. For example, one factory buys cassava chips from Added value for farmer. farmers at a higher price (Rp 50/kg Traditionally, farmers in Ponorogo more) than the highest price for gaplek. district processed cassava roots into Another factory, however, uses a table gaplek. Table 6 compares the added based on root prices. value of chips with that of gaplek for farmers, showing that the Farmers do not readily accept these added value for farmers was methods of determining prices. SURIF 2,175 rupiahs/100 kg of roots.
Table 5. Yield recovery in cassava flour processing calculated from 500 kg of fresh cassava.
Form of cassava Number of Processing Average samples recovery (%) conversion value Min. Max. (%)
Peeled roots 15 73 83 80 Soaked and peeled roots 12 74 88 82 Wet chips before pressing 15 70 88 80 Pressed chips: Screw press 6 61 68 65 Hydraulic press 6 61 66 Dried chips: 34 Screw press 6 29 37 Hydraulic press 6 22 37 Flour 15 30 34 32 Dried starch (byproduct) 9 2 5
SOURCE: Damardjati et al., 1991.
Table 6. Added value of cassava chips compared with that of gaplek for farmers, Ponorogo district, Indonesia, 1992a.
Item Costs in rupiahsb Dried chips Gaplek
Labor costs: Peeling 1,000 1,000 Chipping and drying 1,000 Equipment hire (Rp 10/kg dried chips) 300 Total costs 2,300 1,000
Product price 270 125 Income from product 8,100 5,625 Economic profit 5,000 4,625 Economic income + wage 7,800 5,625 Added income 2,175 0 a. Calculations based on 100 kg of roots, gaplek yield at 45%, chips yield at 30%, 1992 prices of gaplek at Rp 125/kg and sawut (chiplets) at Rp 270/kg, and equipment hire for dried chips at Rp 10/kg. b. Exchange rate: Rp 2,126 = US$1.00 (January 1994).
97 Cassava Flour and Starch: Progress in Research and Development
Consumer Acceptance cracker-like product. Table 8 shows and Marketing the basic ingredients and processing.
Survey on consumer acceptance More than 50% of respondents used cassava flour to bake traditional Consumer acceptance and market foods because they were simple to assessment studies were conducted prepare, were familiar, and the other in two locations with different ingredients readily available. The consumer characteristics: respondents’ different income levels Purwakarta region and Ponorogo were reflected in the different district, both in East Java. The preferences for food types prepared inhabitants of Purwakarta and from cassava flour (Table 9). About Karawang districts in the 43% of high-income consumers Purwakarta region do not produce preferred to process cassava flour cassava and eat it infrequently. In into cake as compared with 21% of contrast, Ponorogo district is a medium- and 29% of low-income major cassava-producing area where consumers who tended to prefer the inhabitants eat cassava as the traditional foods. Table 10 gives second staple after rice. examples of traditional foods in which cassava flour can be used as a A survey was first carried out on substitute for other flours. 115 families in Purwakarta region and 124 in Ponorogo district to Consumer acceptance for discover the acceptability of cassava long-term consumption. The survey flour, its use, and consumer also assessed consumer acceptance preferences. In both areas, more of and the kind of food products than 80% of respondents did not made from cassava flour in the long know of the product but, when it term. Most respondents used as was introduced, received it well much as 50% cassava flour mixed (more than 84% of respondents). with another flour such as wheat, tapioca, or rice for traditional foods More than 50% of respondents (e.g., bala-bale, fried banana, and from both areas used the cassava putu ayu) and cakes. For cookies flour to make traditional foods. and krupuk, relatively little was used Respondents from Purwakarta (Damardjati et al., 1992), although as region also tended to like cookies much as 60% substitution with and cakes (Table 7), whereas those cassava flour, resulting in good from Ponorogo district tended to quality cookies, has been reported prefer traditional foods. One reason (Damardjati et al., 1992). Cassava for the difference may be location: flour and tapioca (cassava starch), the Purwakarta region is larger and mixed at a ratio of 1:3, respectively, most respondents were more have been used in krupuk, resulting educated and skilled in food in an acceptable product (Suismono products. and Wheatley, 1991).
Consumers’ use of cassava In a cooking trial, carried out by flour. Cassava flour can be used as 115 respondents, cassava flour was a substitute flour in wheat-based accepted by about 84% and rejected products. For household by about 15%. The respondents’ consumption, most respondents average demand for cassava flour is preferred to process it into either about 5-7 kg/month. The group that (1) traditional foods, (2) cakes, purchased the most had a medium (3) cookies, or (4) krupuk, a income. Most consumers would
98 Cassava Flour Processing and Marketing in Indonesia
Table 7. Consumer preferences for cassava products in Purwakarta region and Ponorogo district (%), Indonesia.
Product Consumers in Consumers in Purwakarta regiona Ponorogo districta
Like Dislike Like Dislike
Traditional foods 57.0 3.3 59.7 12.1 Cookies or crackers 13.1 0.9 8.9 0.8 Cakes 37.8 1.8 9.7 8.9 a. Number of households surveyed was 115 in Purwakarta and 124 in Ponorogo.
SOURCES: Damardjati et al., 1993; Martini, 1992.
Table 8. Processing and ingredients of products processed from cassava flour, Indonesia.
Type of ingredient Traditional Cookies Cakes Krupuk and process foods
Basic Wheat flour Wheat flour Wheat flour Tapioca flour ingredients Rice flour
Additional Margarine Margarine Margarine Cane sugar ingredients Eggs Eggs Eggs Cane sugar Cane sugar Cane sugar Vegetables Coconut milk
Other Salt Leavening Leavening Salt ingredients Artificial coloring Flavoring Artificial Spices flavoring Flavoring
Process Steamed, fried, or Oven-baked Oven-baked Steamed before roasted frying
Table 9. Consumer preferences (%) among foods prepared from cassava flour, Purwakarta region and Ponorogo district, Indonesia. Samples given during a consumer-preference survey.
Respondent group Processed products
Traditional foods Cookies Cakes Krupuk
Purwakarta region Income group: Low (n = 39) 67.6 16.2 29.7 2.7 Medium (n = 46) 75.6 12.2 21.9 2.4 High (n = 30) 53.3 13.3 43.3 -
Ponorogo district: Urban (n = 57) 66.7 17.5 15.8 - Village (n = 67) 76.1 1.8 24.6 -
99 Cassava Flour and Starch: Progress in Research and Development
Table 10. Traditional food products made with cassava flour as substitute flour, Indonesia.
Local name Cassava Other Brief description flour (%) flour
Bala-bale 50 Wheat Mixture of flour, water, vegetables, and spices. Fried. Cimplung 50 Wheat Mixture of flour, water, sliced jackfruit, and salt. Fried. Nagasari 70 Maize Mixture of flour, coconut milk, sugar, salt, vanilla, maize flour, and cooked. Filled with sliced banana and wrapped in banana leaf. Steamed. Jongkong 50 Rice Dough of flour mixed with coconut milk and salt, and cooked. Filled with sliced palm sugar and thick coconut milk. Wrapped in banana leaf. Steamed. Ongol-ongol 65 Wheat Mixture of flour, water, and sugar, and cooked. Formed, cooled, and sliced. Served with grated coconut. Dodongkal 100 - Cooked flour with water and salt. Dough filled with shredded palm or awug sugar. Served with grated coconut. Biji salak 100 - Small balls made from flour dough and cooked. Served with sweet coconut milk and sliced jackfruit. Bika Ambon 35 Rice Two mixtures of flour, egg, “fermipan,” and coconut water. One mixture worked into a dough. Other mixture cooked with sugar and coconut milk until oily. The two mixtures then combined and baked.
process cassava flour into traditional 250 foods (41.7%) and cakes (21.7%). 200
Marketing problems. During 150 the several years of establishing and developing the cassava flour 100 Tonnage agroindustry, marketing was the first problem faced. Cassava flour was 50 unknown and the market had to be developed. Farmers and farmers’ 0 Jan. Mar. May July Sept. Nov. groups depend heavily on a mill to act as nucleus for collecting and buying Figure 3. Trends in purchasing chips and selling chips. The mill sells mostly to food cassava flour by PT Mariza, Indonesia, 1991. ( = purchasing; = selling.) industries. But the market for processed cassava products is small, with the consequence that the plant 500 (nucleus) becomes overstocked in 400 chips and flour. Operational management also becomes a 300 problem. 200 One company which has Rupiahs per kg expanded its cassava processing 100 operations is PT Mariza, a food company that produces snack foods 0 Jan. Mar. May July Sept. Nov. and cakes. This company has increased its monthly output of Figure 4. Trends in prices of cassava roots and cassava flour in transactions carried cassava flour by over 200% since out by PT Mariza, Indonesia, 1992. 1991 (Figures 3 and 4). ( = flour; = roots.)
100 Cassava Flour Processing and Marketing in Indonesia
Future Development of the flour at distribution level needs to be Cassava Flour Agroindustry determined through the National Food Authority (BULOG). A 10% share from Interrelationships among the total distributed by BULOG will determinants in the agroindustry’s suffice to warrant cassava flour development marketing. The increased agroindustry will speed up the development of The main interacting participants in cassava products, the prices of which the cassava flour agroindustry are will be heavily influenced by their (1) farmers or farmers’ groups, quality. (2) KUD or processor, (3) factory and distributors, and (4) consumers Consumers. Even with BULOG’s (Table 11). The four determinants intervention in distributing cassava are (1) policy, (2) infrastructure, flour, distributors and retailers are (3) participation, and (4) technology. responsible for making it readily available to consumers. Three Farmers or farmers’ groups. methods are to undercut the prices of Basic policy needs to be constructed at other flours, promote through mass farmer level. An example is media, and encourage food and catering determining a suitable floor price for industries to increase their use of chips, to motivate farmers in cassava flour as a raw material in processing. Small farmers should processing food. obtain credit from banks through simple procedures and flexible Supporting activities guarantees. They should also receive extension and training in skills for To support efforts in developing the developing both the cassava flour agroindustry, certain governmental agroindustry and its processed policies are urgently needed. These products. would help improve quality; create a production environment advantageous KUD or processor. The KUD or to processors, distributors, and processor also expects simple farmers; and change consumer procedures and flexible guarantees attitudes toward cassava. These when obtaining credit from banks. To policies are: ensure the agroindustry’s continuity at village level, each small industry’s (1) Price and distribution policies. Price share of production should be and distribution policies for cassava protected. Chip prices should also be products (cassava flour and chips) sufficiently competitive. of defined levels of quality can encourage increased production The village KUD or processor has a and improved product quality. The relatively low management capability, ensuring of cassava raw material needing guidance in its operational supplies requires an established management. Simple and easily distribution mechanism. installed equipment with locally available spare parts is to be preferred. The continuous distribution of The demand for such equipment will cassava flour throughout the year provide opportunities for local will encourage farmers to increase workshops. cassava production and ensure a continuous supply for processors. Industry and distributor. To BULOG is expected to play an speed up distribution of cassava flour important role in the distribution to consumers the market share of the system, which will then develop
101 Cassava Flour and Starch: Progress in Research and Development intervention b BULOG -through distribution Good Consumer b as “foster-parent,” but b no market monopoly flour - Can be mixed with other flour distributor level, BULOG - Export promotion - Cassava flour marketing at Industry Subject or processor a Credit ensured Credit - -flexibility Assurance equipmentcosts operational equipment - Spare parts available - Products from cassava flour - Basic price of chips - Relatively cheap - Easy credit - Training-chippingfor Credit - Market implementation- Processing efficiency - Credit for equipment and- -processingin value Added Market information management - Processing efficiency -creditfor Facilities - Spare parts available -intensive Labor flour supplies -service of role Improvement processed cassava products media - Standard quality of chips and - and flour packaging packaging Attractive -ensured Credit -flexibility Assurance - Basic price of cassava flour - Protection of production share - BULOG controlled -price Ceiling Farmers or farmers’ group KUD Policy Table 11. Matrix correlation of determinants, by participating groups, in the cassava flour agroindustry, Indonesia. Determinant a. Koperasi Unit Desa (village union cooperative). b. BULOG = National Food Authority, Indonesia. SOURCE: Adnyana et al., 1991. Infrastructure - ExtensionParticipation -expectation Price Technology - Guidance in operation -expectation Price - Simple and easily installed - Facilities for promoting - Simple and easily installed - Efficient - - Continuity of chips and cassava Promotion through mass -taste of Competitiveness -technique Serving
102 Cassava Flour Processing and Marketing in Indonesia
through the self-supportive nature and Dharma Pertiwi; of the existing market. nongovernment organizations, including social and professional (2) Support for industrial and export organizations; and the mass media. diversification. Developing cassava flour processing plants is the main step toward supporting the Conclusions development of cassava industries in general. The consistent demand Developing the cassava flour for raw material for cassava flour agroindustry represents for Indonesia production has already increased an alternative for diversifying cassava at farmer level. To develop, these products. It can potentially increase industries need support in farmer incomes, extend marketing, providing an environment that will support food diversification, reduce attract investors. wheat imports, and contribute to the development of various chemical and Quota restrictions have already food industries. Cassava flour severely limited the possibilities of processing requires the development of increasing the traditional export of techniques and equipment for peeling, dried cassava (chips and pellets). washing, soaking, drying, chipping, But export volumes can be pressing, and milling. expanded for nontraditional commodities such as fructose, The cassava flour agroindustry can sweets, sorbitol, and modified be structured on three models, starch. Various food products with according to capital, capability, potential as export commodities knowledge, and distribution systems of have already been formulated with the raw material. These models are cassava flour as raw material. based at farmer level (model 1); farmer group level (model 2); and mill or plant (3) Extension should be aimed at belonging to a group of private various levels of the community: companies or cooperatives as a nucleus farmers and their families, in the processing and marketing processors, and other groups. system (model 3). The mills act as Extension materials should be processors of intermediate products, structured according to each that is, dried chips, from models 1 and targeted level of the community. 2 to be processed into cassava flour as final product. An economic feasibility (4) Campaigns and promotion. The analysis showed that a cassava flour Government can help change the agroindustry is feasible at the village community’s attitudes toward level when it is based on the three cassava through such activities as models being structured into a system. promotion, extension, expositions, and cooking festivals. Cassava flour can be processed into four groups of food product: traditional (5) Community uses of cassava flour. foods, cookies, cakes, and krupuk. The Catering services and bakeries higher the income and education of the would be the major consumers household mother, the more likely that of cassava flour, especially by cassava flour will be accepted for use in substituting for wheat flour in traditional foods and cakes. As many their products. Other promoters as 84% of consumers would accept include governmental and cassava flour, and most of these could semigovernmental organizations buy 4 to 7 kg of cassava flour per such as KORPRI, Dharma Wanita, month. With promotion and improved
103 Cassava Flour and Starch: Progress in Research and Development supplies, the flour therefore has a high ______; Widowati, S.; and Dimyati, A. potential to develop a niche in urban 1990. Present status of cassava markets, especially as supplement to processing and utilization in Indonesia. In: Howeler, R. H. (ed.). cereal flours. Proceedings of the Third Regional Workshop of the Cassava Research Marketing is still a major Network in Asia, Oct. 22-27, Malang, constraint to expanding the cassava Indonesia. CIAT, Cali, Colombia. flour agroindustry. The PT Mariza’s p. 298-314. successful expansion was supported ______; ______; and Rachim, A. 1992. by its ability to diversify its products Development of cassava and markets. Governmental support processing at the village level in and policy making is still necessary to Indonesia. In: Product development create a favorable production for root and tuber crops. Centro Internacional de la Papa (CIP), Lima, environment and improve quality at Peru. p. 261-273. every step of the production system to match market demands. ______; ______; and ______. 1993. Cassava flour production and consumers’ acceptance at village References level in Indonesia. Indones. Agric. Res. Dev. J. 15(1):16-25.
Adnyana, M. O.; Rachim, A.; Damardjati, Dimyati, A. and Manwan, I. 1992. National D. S.; and Basa, I. 1991. Potensi dan coordinated research program: Kendala Pengembangan Agro-industri cassava and sweet potato. Central Tepung Kasava dalam Sistem Research Institute for Food Crops Usahatani Terpadu di Lampung. (CRIFC), Bogor, Indonesia. 61 p. Puslitbangtan, Bogor, Indonesia. Martini, R. 1992. Study on cassava flour as CBS (Central Bureau of Statistics). 1988. Food substitution ingredient on food balance sheet in Indonesia, 1986-87. industry and family level in Jakarta, Indonesia. Ponorogo. S1 thesis. Bogor Agricultural University, Bogor, ______. 1990. Food balance sheet in Indonesia. Indonesia, 1988-89. Jakarta, Indonesia. Rusastra, I. W. 1988. Study on aspects of national production, consumption ______. 1991. Food balance sheet in and marketing of cassava. Indones. Indonesia, 1989-90. Jakarta, Agric. Res. Dev. J. 7:57-63. Indonesia.
______. 1992. Food balance sheet in Suismono and Wheatley, C. 1991. Indonesia, 1990-91. Jakarta, Physico-chemical properties of the Indonesia. “krupuk” product on some of the formulates of cassava composite flour. In: Suismono (ed.). Cassava ______. 1993. Food balance sheet in roots: characteristic, utilization and Indonesia, 1991-92. Jakarta, analysis methods. CIAT, Cali, Indonesia. Colombia. 21 p. ______. 1994. Food balance sheet in Indonesia, 1992-1993. Jakarta, Unnevhr, L. J. 1990. Assessing the impact of Indonesia. research on improving the quality of food commodities. In: Methods for Damardjati, D. S.; Seytono, A.; Widowati, S.; diagnosing research systems Suismono; and Indrasari dan Sutrisno, constraints and assessing the impact S. D. 1991. Lap. model of agricultural research. Agro-industri tepung Kasava di International Service for National Pedesan. I. Analisis petensi wilayah Agricultural Research (ISNAR), The pengembangan dan penyajian pilot Hague, the Netherlands. p. 101-116. plant. Bogor, Indonesia.
104 World Production and Marketing of Starch
CHAPTER 13
WORLD PRODUCTION AND MARKETING OF STARCH1
Carlos F. Ostertag*
Introduction Main Starch Sources
Starch production is a major world Starch is extracted from maize, agroindustry, with a volume of sweetpotatoes, cassava, potatoes, around 33 million tons per year, and wheat, rice, sorghum, sago palm, a value of US$14 billion (Jones, 1983; arrowroot, and bananas (AVEBE, Marter and Timmins, 1992; 1989; Jones, 1983). Developed Titapiwatanakun, 1993) (Table 1). countries grow most of the world’s Starch is extracted primarily from maize, potatoes, and wheat, whereas cereals and roots through processes developing countries grow most of the that separate fiber and protein. sweetpotatoes and cassava. For example, China produces almost 85% Demand for starch is influenced of world’s sweetpotatoes (Rhem and by its versatility. Almost all major Espig, 1991). industries use starch and, as a result, industrialization normally coincides These starches differ from each with a significant increase in the other in their granule forms and sizes, demand for this raw material (Lynam, contents of amylase and amylopectin 1987c). (the two types of glucose polymers present in starches), swelling Three main classes of capacities (i.e., capacities to absorb starch-based products exist: water), and gelatinization unmodified or native starches (UMS), temperatures (Jones, 1983). modified starches (MS), and sweeteners. Modified starches are In the early 1980s, 77% of world’s those in which one or more of their starch was estimated to derive from physical and chemical properties have maize (Jones, 1983), mainly because been changed slightly (Jones, 1983). 91% of the starch produced in the USA, the world’s largest producer, was from maize (Farris, 1984). The increase in yield per hectare, from 2.4 t in 1950 to 7.6 t in 1986, contributed significantly to this cereal’s importance (Lynam, 1987c).
Table 1 shows the relative * Cassava Program, CIAT, Cali, Colombia. importance of different starch 1. No abstract was provided by the author. sources. Two reasons for the
105 Cassava Flour and Starch: Progress in Research and Development
Table 1. Estimated world starch production (1992) (thousand tons)a.
Region or country Raw material Total Percentage of world Maize Sweet- Cassava Wheat Potato Other production potato
North America: 13,450 - - 200 55 20 13,725 41 USA 13,200 - - 50 50 20 13,320 40 Canada 250 - - 150 5 - 405 1
Latin America 1,000 - 330 - - - 1,330 4
European Union 3,400 - - 1,400 1,200 - 6,000 18
Ex-USSR and 300 - - - 300 - 600 2 Eastern Europe
Africa - - 20 - - - 20 <1
Asia: 3,020 4,165 3,442 165 400 30 11,222 34 China - 4,000 300 - - - 4,300 13 Japan 2,500 120 - 150 400 - 3,170 10 Thailand - - 1,800 - - - 1,800 5 Indonesia - - 800 - - - 800 2 India 200 - 350 - - - 550 2 Vietnam - - 90 - - - 90 <1 Philippines 75 - 17 - - - 92 <1 Malaysia - - 70 - - - 100 <1 Taiwan 45 15 15 15 - 30 90 <1 South Korea 200 30 - - - - 230 1
Australia 50 - - 300 - - 350 1
Total 21,220 4,165 3,792 2,065 1,955 50 33,247 100 64% 13% 6% 6% 6% 0% 100% a. Includes modified starches and sweeteners.
SOURCES: Estimates based on Jones, 1983; Marter and Timmins, 1992; Titapiwatanakun, 1993.
decrease in the proportion of maize Holland), Japan, and Eastern Europe. starch (64%) are (1) the table includes China accounts for almost all of the estimates by Marter and Timmins world’s production of sweetpotato (1992) of starch production in China, starch, whereas the EU, Australia, derived mainly from sweetpotato, and Canada dominate wheat starch which Jones excluded in the 1983 production (Table 1). estimate; and (2) Thailand has greatly expanded cassava starch production The maize starch produced in recently (Titapiwatanakun, 1993). Japan is derived mainly from imported U.S. maize, as used to be Production of maize starch is the case for the EU. This region concentrated in the USA, Japan, and now locally produces 99% of its the European Union (EU). Asia is the maize requirements for starch chief cassava starch producer, production (Leygue, 1993). Local primarily Thailand, Indonesia, China, maize-processing capacity has and India; with Brazil, in Latin displaced native starch sources such America, also an important producer. as rice, sweetpotatoes, potatoes, and Production of potato starch is cassava. For example, in Japan, in centered in the EU (especially 1962, 80% of the starch produced
106 World Production and Marketing of Starch was derived from sweetpotatoes and obtain chemical derivatives not potatoes. But this share fell to 20% possible from cellulose or sucrose. by 1982, displaced by U.S. maize. Starch can also be separated into The main reason was that Japanese amylose and amylopectin, and can be starch was used mostly for producing used in solvolysis with alcohols (Koch sweeteners, a category for which the and Roper, 1988) (Figure 1). technology for maize wet-milling is very advanced (Lynam, 1987c). A simple way to classify starch-based products is as follows: UMS, MS (e.g., dextrins, Simplified Classification of pregelatinized starches, and oxidized Starch-Based Products starches), starch derivatives (e.g., esters, ethers, and cross-linked Starch is a versatile raw material starches), and sweeteners (glucose compared with other carbohydrates. syrups, high fructose syrups, Native starch can be modified or dextrose, and maltodextrins) (Jones, chemical derivatives obtained from it 1983; Koch and Roper, 1988). Starch by using relatively simple processes. derivatives and sweeteners are used Starch is dispersible in cold water primarily in the food industry. and has a higher reactivity than the highly polymeric cellulose. Starch is Native starches are marketed dry, also highly susceptible to partial or under different grades for human and total hydrolytic degradation by acids industrial consumption. Most or enzymes, yielding oligomeric or developing countries produce only monomeric products, which, in turn, this type of starch, except for those can be further modified or used to with Corn Products Corporation (CPC)
Process Product
Separation * Amylose * Amylopectin
* Modified starches Mechanical/thermal * Pregelatinized starches treatment * Dextrins
Esterification Native Etherification * Starch derivatives starch Cross-linking
Transglicosilation * Glucosides (solvolysis)
* Monosaccharides Hydrolysis * Disaccharides * Oligosaccharides * Maltodextrins
Figure 1. Starch-based products. (After Koch and Roper, 1988.)
107 Cassava Flour and Starch: Progress in Research and Development subsidiaries, which also produce MS Main Starch Producers (Jones, 1983). Table 1 shows that starch production Modified starches are those that in the USA, almost exclusively maize have been changed slightly in one or starch, accounts for 41% of world more of their physical and chemical production. Asia has become an properties. Modification aims to important starch producer, adjust the product to the particular contributing to more than one-third of needs of a client or to imitate a world production. The major competitive product. The range of producers are China (sweetpotato), modifications and processes is vast Japan (maize), and Thailand and complex but can be (cassava). Asian starch is extracted summarized as follows: mainly from sweetpotatoes (38%), cassava (31%), and maize (28%). (1) Pregelatinized type by feeding a Although maize starch is from U.S. starch suspension on to a heated maize, the other starches are rotating drum. obtained from local raw materials. (2) Dextrin type from dry chemical treatment. No exact records of sweetpotato (3) Wet chemical treatment, starch production in China exist but, including thin boiling and according to Marter and Timmins oxidized starches. (1992), the volume could be about (4) Other modifications, including 4 million tons/year. Processing is at the use of catalysts and household level in villages and the cross-linking and etherifying starch is used primarily for making agents (Jones, 1983). noodles, a traditional oriental food.
The term “sweetener” refers to Starch consumed in Japan can be products such as glucose syrup, categorized as (1) starch obtained high fructose syrup (HFS), and from local crops such as potatoes and dextrose. Sweetener production is sweetpotatoes, (2) starch derived from based on acid or enzymatic imported raw materials such as maize hydrolysis of starch. Chemically, and wheat, and (3) imported starches, glucose and dextrose are such as cassava, sago, and potato synonymous, but, commercially, starches (Jones, 1983). “dextrose” is used to describe the pure crystalline product and The EU produces nearly 18% of “glucose syrup” products obtained world starch, principally from maize, from incomplete starch hydrolysis wheat, and potato. France alone (Jones, 1983). accounts for one quarter of this volume (Leygue, 1993). Obtaining By subsequent complex starch from wheat flour through processing, based on enzyme action, wheat-washing technology (gluten HFS can be obtained. This product separation) has increased since 1983, has grown substantially in with an annual growth rate of 15%. importance, particularly in the USA, This source has displaced maize where it was introduced in 1968. starch to a significant extent (Leuch, Usually based on maize, it is known 1990). Starch production in the EU as high fructose corn syrup (HFCS) has grown at an annual compound in the USA and as isoglucose in rate of 4.4% during 1981-1990 (Koch Europe (Jones, 1983). et al., 1993).
108 World Production and Marketing of Starch
Latin American starch production reduction in the domestic price of accounts for 4% of world production cereals in the EU indicates that the and consists of maize and some farm price of local roots will decrease cassava starches. Brazil dominates in Thailand, liberating raw material the production of both starches. for producing cassava starch. Thai cassava starch exports have increased The starch industry mostly at an annual growth rate of about supplies its own domestic markets. In 14% since 1975 (Atthasampunna, 1980, excluding internal EU trade, 1990; Lynam, 1987b; only 4% of world production Titapiwatanakun, 1993); for example: (600,000 t/year) was estimated to be exported (Jones, 1983). Since then, Year Exports in tons starch production has expanded to such an extent in Thailand and China, 1975 145,000 that exports have more than doubled, 1980 248,000 to almost 1.5 million tons. Almost 1985 497,000 70% of Thai starch is exported, mainly 1989 646,000 to the USA, Japan, and Taiwan 1991 1 million (Titapiwatanakun, 1993).
International trade is concentrated Current Starch Markets in UMS, mainly from Thailand, China, Indonesia, and Brazil, and consists In most countries, starch chiefly of cassava and sweetpotato consumption is highly correlated with starches (Jones, 1983; Shuren and production. Exceptions are those Henry, 1993; Titapiwatanakun, 1993). countries where starch production is The major markets for exported starch primarily export-oriented (e.g., are Japan, Taiwan, the USA, and the Thailand and China) or where starch EU (Jones, 1983). is imported (e.g., Taiwan and, to a lesser extent, Japan). The recent high growth rate of the starch industry in Thailand is worth General uses studying. The Thai starch industry has confronted two limitations: first, Starch has one of the widest ranges of the high tariffs for starch imports in end-uses of any product derived from almost all nations except the USA; and vegetable sources. It is a good source the second, competition with the pellet of carbohydrate but in the food and chip export market for raw industry it is used mainly as a material. The domestic EU price for thickener, filler, binder, stabilizer, or cereals determines local root prices, texture improver. Some examples of which is why roots for the starch these uses are in canned and industry are so expensive. The starch powdered soups, instant desserts, industry, in turn, has to compete with custard powder, sausages and the low international maize prices processed meat, sauces, bakery (Lynam, 1987c). products, confectionery, and ice cream. Sweeteners such as syrups But the establishment of export are used for soft drinks, pastries, and quotas for Thai pellets to the EU in the canned goods; this segment has early 1980s lowered domestic prices of shown the most growth in the last cassava roots and led to a doubling of 25 years. Edible starch is also used cassava starch exports (Lynam, in the pharmaceutical and brewing 1987c). Titapiwatanakun’s study industries (Jones, 1983). (1993) of the impact of the recent 29%
109 Cassava Flour and Starch: Progress in Research and Development
The industrial uses of starch for sugar in every area except dry and starch products are numerous. mixes or wherever a nonhygroscopic Among the most important are in sweetener is required, as is the case the paper and board industry for hard candy and table sugar (Long, (printing papers, coated papers, 1985). corrugated board), adhesives (labels, laminating, gummed paper, tape), The end-uses for UMS and MS in textiles (sizing, finishing), oil-well the USA (1980 data from Jones, 1983) drilling (drilling “mud”), dye stuffs, include: and the building, metal, and chemical industries (Jones, 1983). (1) Paper industry (60% of UMS and 50% of MS), including for sizing, Uses in the USA coating, and corrugation. (2) Food industry (20% of UMS and More than 95% of the starch 20% of MS), including for currently used in the USA is ingredients in cookies and obtained by wet milling maize. In convenience foods (e.g., instant 1992, 48% of the wet milling output soups, desserts, and frozen was destined for HFCS production, dinners). 25% for glucose and dextrose, and (3) Other important industrial users 27% for actual maize starch (USDA, are the brewing, pharmaceutical, 1993a). These figures exclude and adhesive industries (20% of ethanol production based on the wet UMS) and the textile industry milling technology but it should be (30% of MS). noted that more than 10 million tons of maize were used for this purpose in the USA in 1992 (USDA, 1993a). Table 2. Production of the principal starch products in the USA in millions of tons a Table 2 shows starch production (mill. t) . and relative weight for 1980 and Product 1980 1992 1992 of the main starch-derived products in the USA. The end-use (mill. t) (%) (mill. t) (%) as sweetener is prominent, Maize starch representing more than 70% of the HFCSb 1.91 31 6.00 45 total. The high growth of the HFCS Glucose syrup 1.86 30 2.90 22 segment can also be noted for the Dextrose 0.41 7 0.60 4 absolute domination of the soft Subtotal drink market for sweeteners since sweeteners 4.18 68 9.50 71 1985 (Claassen and Brenner, 1991). Unmodified 1.18 19 2.20c 16 HFCS production is divided into Modified 0.68 11 1.40c 11 HFCS-55 (containing 55% fructose) Other 0.06 1 0.10c 1 with a market share of 58% and Other starches HFCS-42 (containing 42%) with (e.g., wheat, 42%. potato) 0.07 1 0.12 1 Total 6.17 100 13.32 100
The use of maize-based a. Excludes ethanol production derived from wet sweeteners, especially HFCS, has milling maize. grown dramatically because of their b. HFCS = High fructose corn syrup. excellent quality, their usefulness as c. C. F. Ostertag, 1993, unpublished data. functional agents in foods, and their SOURCES: 1980 data: Jones, 1983. lower cost versus sugar (Long, 1992 data: Farris, 1984; Kirby, 1990; 1985). HFCS is a direct substitute USDA, 1993a.
110 World Production and Marketing of Starch
Almost 100% of the starch-based 1980-1987 because of its special production of sweeteners is destined chemical properties. At the same for the food industry. More than time, the consumption of potato 70% of the HFCS production is used starch also increased, whereas that of by companies producing carbonated maize starch decreased (Christmann, soft drinks; 90% of HFCS-55 is used 1991). The demand for starch overall for carbonated soft drinks (USDA, in Germany by nonfood industries in 1993b). Other uses for sweeteners the year 2000 is predicted to be include pastries, canned fruit, between 600,000 and 800,000 t, dessert dairy products, and and for the EU, between 2.5 and dressings and ketchup. Apart from 3.0 million tons (Christmann, 1991). their sweetening properties, they are also useful for controlling Uses of potato starch hygroscopicity, texture, freezing temperature, and viscosity (Long, The chief world markets for potato 1985). starch, mostly located in the EU, are the following industries: food, paper, Uses in the EU textiles, and mineral oil (additives for oil-well drilling) (AVEBE, 1989). In Of the 6 million tons of starch the early 1980s, these uses were produced in the EU, 54% is used by distributed in the USA as follows: the food industry and the remaining 33% for paper, as a cationic 46% by the nonfood sector, including derivative; 30% in the food industry paper (19%), chemicals and in native or modified form for fermentation (13%), corrugation (7%), preparing soup mixes, puddings, and and others (7%) (Koch et al., 1993). sweets in general; 19% for adhesives, Other relatively new uses in the EU preferably in dextrin form; and 15% are for the production of ethanol, in pregelatinized form as an additive plastics, and polymers (Agra Europe, in oil-well drilling. The latter segment 1990). The annual growth rate of exhibits the highest growth rate nonfood markets (4.8%) has been (Mitch, 1984). greater than the global market (4.4%) (Koch et al., 1993). Uses in Japan
Starch is consumed in its native In 1980, almost 60% of the starch (29%), modified (17%), and hydrolyzed produced in Japan was for forms (54%). Hydrolyzed starch is sweeteners, mainly HFCS, derived used in sweets, beverages, fruit primarily from U.S. maize, but also preparations, and pastries (Koch et from sweetpotato and potato starches. al., 1993). Nearly 15% of the starch was destined for MS production, principally based Of the 1 million tons of starch on imported maize; the main MS employed by industry in the then produced was oxidized starch. Other West Germany (1987), 41% was used important uses were for paper, for the following product categories: cardboard, and textiles (7%); fish adhesives, pharmaceuticals, paper products such as kamaboko (7%); and cardboard, soap, chemicals, dyes, beer (3%); and monosodium paints, building materials, and rubber glutamate (MSG), a popular flavor products (Christmann, 1991). enhancer in Asian cuisine (1%). The rest of the starch (12%) was used The use of wheat flour in nonfood chiefly for food products (Jones, industries in West Germany increased 1983). Currently, Japan produces from 1,000 to 90,000 t during almost 2 million tons of HFCS.
111 Cassava Flour and Starch: Progress in Research and Development
Uses in Taiwan In Thailand, for the 510,000 t of starch consumed domestically, the Taiwan is a major importer of starch, main markets in 1991 were principally cassava starch, which, in household use and food (e.g., 1983, was used mainly for preparing noodles), 33%; MSG and lysine, 19%; maltose for bakery products and glucose syrup, 15%; paper industry, sweets and alpha starch for eel feed. 9%; textiles, 3%; plywood, 1%; and Other uses for MS were adhesives for others, 13% (Titapiwatanakun, 1993). corrugated cardboard, dextrins, When comparing these figures with ingredients for food products such as 1983 data (Lynam, 1987b), the food noodles, and other uses in the textile and glucose markets present the and paper industries. Potentially, highest rates of growth—the glucose MSG can be the largest consumer of market did not even exist in 1983. starch but molasses are normally The markets for MSG, lysine, and used. When the price of molasses end-uses in the paper industry, in goes up, cassava starch is preferred contrast, have decreased significantly. (Jones, 1983). Predictions for the year 2001 Other Asian markets suggest that the consumption by the food industry will fall to 18%, Asians tend to use cassava and whereas the share held by MSG and sweetpotato starch more for industrial lysine will rise to 27%, and that of uses than for human consumption. the paper industry to 15% For example, the percentage of (Titapiwatanakun, 1993). Thailand cassava starch destined for human exports MS mostly to Japan. consumption fell from 65% to 50% between 1966 and 1980 (Ghosh, About 10% of Indonesian 1988). In Indonesia, 3% of cassava cassava production is processed to roots in 1983 were directed toward obtain starch, which is mostly used starch production, whereas by 1988 (65%) to make krupuk, a crunchy this percentage had increased to 10% native food. Another 15% of cassava (Damardjati et al., 1990). starch is used for other foods, 10% for textiles, and 3% for glucose Sweetpotato and cassava (Damardjati et al., 1990; Lynam, starches in China have traditionally 1987a). been used to prepare noodles and MSG. Almost half the starch Cassava starch in India is production is directed to noodles. Of mainly used for household the 200,000 t of MSG produced consumption and to prepare glucose annually, 90% are prepared from and dextrins. In the northern sweetpotato and 10% from cassava states, it is also used in the textile starch (Shuren, 1990). industry (Padmaja et al., 1990).
Other industrial uses of starch in Cassava starch production in the China include sweeteners such as Philippines is destined chiefly for the glucose syrup (100,000 t/year), food industry and for glucose. Other medical glucose, maltose, and HFS. minor markets include the Production of HFS is low because it pharmaceutical, paper, textile, and cannot compete with the adhesive industries (van Den et al., sophisticated sugar industry (Shuren, 1990). 1990). China has also pioneered the production of sophisticated chemical products.
112 World Production and Marketing of Starch
Uses in Latin America the EU (Sasson, 1990). The following year, the main soft drink Starch in Brazil is used for household manufacturers in the USA decided to consumption, and in the food (e.g., as increase the proportion of fructose a thickener, stabilizer in processed syrup from 50% to 100% (Sasson, meat, base for colors and aromas, 1990). Per capita consumption of and in bread making) and HFCS rose almost three-fold between pharmaceutical industries. In 1980 and 1988 (Table 3). The growth nonfood industries, it is employed to rate of the HFCS began to fall in 1985 manufacture adhesives, paper, (The advance of..., 1991) after explosives, and biodegradable plastics conquering the soft drink market, the (Cereda, 1991; I. C. Takitane, 1992, main market for sweeteners in the USA personal communication). (Claassen and Brenner, 1991).
The market for sweeteners The annual production of HFCS in the USA in 1992 was 6 million tons, Of the market segments for starch, 58% of which corresponded to that of sweeteners deserves special HFCS-55 and 42% to HFCS-42 (USDA, attention because it has displayed the 1993b). This volume represents 70% highest growth in the last 25 years. of world production, followed by Japan The birth of enzyme engineering (The advance of..., 1991). allowed the low-cost conversion of starch to D-glucose and then to a The current world production of mixture in equilibrium of D-glucose HFS, about 8.5 million tons, is and D-fructose (HFCS) exhibiting the concentrated in developed countries. same degree of sweetness as invert In the EU, the annual HFS production, sugar from sugar cane or sugar beet. about 500,000 t, has been voluntarily restricted to protect the sugar beet High fructose corn syrup. HFCS industry (Coutouly, 1991). contains from 55% to 90% fructose (a median of 60%) but the most common But an increasing proportion of in the U.S. market are HFCS-55 and growth is expected in developing HFCS-42. The HFCS-55 is slightly countries, which have alternative sweeter than sucrose. A fructose with sources such as cassava, rice, wheat, a 97% purity can be obtained from and sorghum. Currently, these syrups (Sasson, 1990). starch-based sweetener production is
When HFCS was launched in 1968, it immediately captured 30% of Table 3. Growth of annual consumption (kg per the market for sugar in the USA and capita) of caloric sweeteners in the USA doubled the amount of starch (1965-1992). produced by the maize wet-milling Year Sweetener industry (Whistler, 1984). The success of the HFCS resulted from the Glucose High Dextrose Sucrose syrup fructose protection of the domestic sugar syrup industry, reflected by high internal prices, and the lowered price of maize 1965 5.6 .0 1.9 44.0 due to yield increases (Lynam, 1975 7.4 3.1 2.3 41.6 1987c). 1980 8.3 7.0 1.6 38.6 1985 8.9 20.0 1.8 29.1 1992 9.6 23.5 2.0 29.3 In 1984, 3.5 million tons of HFCS were produced in the USA, almost SOURCES: Farris, 1984; Higley and White, 1991; 1 million in Japan, and 200,000 in USDA, 1993b; Whistler, 1984.
113 Cassava Flour and Starch: Progress in Research and Development growing faster in Asia and Latin Marketing Opportunities for America (Claassen and Brenner, Developing Countries 1991). Some countries, like China and Vietnam, already have small HFS According to Jones (1983), trade industries. But the international barriers such as duties, levies, and sweetener trade is small, with the quotas limit export opportunities, USA as a net importer—it purchased particularly to the EU and Japan. almost 200,000 t of HFCS from Price competitiveness is the other Canada in 1992 (USDA, 1993b). major factor affecting market prospects. Glucose syrup. In contrast, processing for glucose syrup is “Mass” and “specialized” markets simpler. Hence, its production is must be distinguished: in the mass widespread, even in the developing market most UMS must compete with countries of Asia (e.g., Thailand, one another, with the result that the China, India, the Philippines, and cheapest, assuming acceptable Indonesia) and Latin America (in quality levels, enjoy market success. countries with CPC subsidiaries). In contrast, the specialized Marketing factors. Table 3 market is a small segment of the UMS shows the growth of per capita market, where end-users require consumption of sweeteners in the specific characteristics, such as a USA from 1965 to 1992. By 1985, certain granule size or pasting the combined per capita consumption temperature, that can only be of sweeteners surpassed that of supplied by one or two particular sugar. starches. But, because other starches can be profitably modified to The world sweetener market, reproduce the desired properties, however, is divided into caloric (e.g., these modified starches (usually sugar and HFS) and noncaloric (e.g., maize or sweetpotato) may gradually saccharine and aspartame) reduce the UMS’ share in the sweeteners. Total consumption of specialized market. For example, noncaloric sweeteners is equivalent, after World War II, much of the USA’s in sweetness, to 8 million tons of cassava starch imports were sugar, similar to the equivalent HFS substituted with cheaper maize production. As a reference, total starch (Lynam, 1987c). sugar production exceeds 110 million tons (The advance of..., 1991). Future prospects for starch exporters in developing countries vary Prices of the different greatly with regard to the mass starch-derived sweeteners in the U.S. market. In the EU, for example, with market in July 1993 were HFCS-55, the current restrictions, the outlook US$0.52/kg; HFCS-42, $0.47; for import growth is nil. In Japan, glucose, $0.33; and dextrose, $0.54. import growth prospects are limited to These prices were considered to be achieving the full quota. If the high and a reduction was expected in exporter can compete with U.S. maize the fourth quarter (USDA, 1993b). prices, then considerable potential Prices respond to the cost of maize exists in the USA. and other inputs and to demand, which is high in summer and declines International trade in MS and in other seasons. Dextrose is sweeteners is small. Sweetener characterized by a high but stable exports are limited. Most MS exports price (USDA, 1993b). correspond to dextrins. Traditionally,
114 World Production and Marketing of Starch developing countries participate little petrochemical products, but focus in this trade. The main potential lies should be given to preparing and in increasing the exports of the synthesizing new compounds with already modified cassava starches specific and improved properties being produced in the USA, Japan, (Koch and Roper, 1988). and the EU from imported cassava starch. Ethanol
For developing countries, modified One new compound of high potential starch exports would earn added is ethanol. In the USA, since the late value and are likely to have easier 1960s, 95% of ethanol has been access to foreign markets. But a high produced from wet milling maize. level of technical expertise and a close Initially, ethanol was used to blend relationship between modifier and with gasoline at a 1:9 ratio to produce end-user are desirable. Thailand and “gasohol.” Currently, this blend China are currently increasing represents 8% of gasolines sold in the exports of MS to Japan. USA. New uses later emerged: as an octane enhancer in gasoline, and as In view of the uncertain export an oxygenate to reduce the opportunities, prospective starch environmental pollution of producers in developing countries are automobiles. In 1992, ethanol recommended to concentrate first on production reached almost 1 billion their domestic markets, then expand gallons. Ethanol is now not only to neighboring markets, before selling feasible but will be the predominant on the international market. energy alternative in the future. The main oxygenate competitor for The domestic markets for UMS ethanol is methyl tertiary butyl ether will grow if the UMS-using industries (MTBE) (Hiunok, 1993; Russo, 1993). (food, textile, paper and cardboard) develop. Demand for MS, sweeteners, Germany and the EU are studying and, in countries where sugar is the feasibility of replacing scarce or expensive, HFS may arise. petroleum-derived products with Other uses for starches are for renewable raw materials such as composite flours and biotechnological starch, among others. Analyses are applications. being conducted on substituting 10% of diesel and heating oils and 5% of petroleum with renewable raw New Market Perspectives materials such as starch, and on the for Starch greater use of renewable raw materials as fuel (Schmitt, 1988). Because of starch’s versatility, new uses arise every year. It is also an Biodegradable polymers excellent example of a renewable raw material. It should be used more The USA is increasingly concerned widely in the medium and long term, with environmental pollution caused taking into account three aims: (1) to by its production processes and the preserve natural resources, (2) to disposal of its end products. This has produce biodegradable products that forced the plastic industry to look for are environmentally friendly, and alternative raw materials and to make (3) to reduce agricultural surpluses its products more recyclable and (Koch and Roper, 1988). biodegradable (Beach and Price, Starch-based derivatives can 1993). substitute to some extent for
115 Cassava Flour and Starch: Progress in Research and Development
The current use of biodegradable about 4.5 million tons of adhesives, of polymers, mostly based on maize, in which 40% were natural. Maize the USA has been for items where starch dominates the market for disintegration after use is of direct natural adhesives with an annual benefit. Some examples are consumption of 1.6 million tons agricultural mulch films, planting (USDA, 1993a). containers and protectors, hay twine, surgical stitching, medicine capsules, Organic chemicals and compost bags. Agricultural pesticide firms are also examining the Agricultural products are increasingly use of starch-based polymers to considered as alternative raw encapsulate products (Beach and materials for organic chemicals. Price, 1993). Within the common ground shared by agricultural and chemical industries, Markets for biodegradable a new industry, labeled “green polymers in the USA are food refinery,” may result. The starch packaging, nonfood packaging, industry competes with that of personal care and medical products, glucose syrup to supply fermentation and other disposable products. But substrata. Of the possible because the U.S. Government has not biotechnological processes, the most regulated the use of biodegradable viable in the short and medium terms packaging for food, the key market in involve producing energy, the near future will be for nonfood fermentation products such as amino packaging. By 1992, biodegradable acids and other organic acids, polymeric resins had captured 0.06% biodegradable plastics and of the market for plastic resins used surfactants, antibiotics, and by the nonfood sector, representing biocatalysts (Malerbe, 1990). 2.3 million kg of a total of 3.6 billion kg (USDA, 1993a). China has pioneered the development of refined chemical Biodegradable polymers compete products such as sorbitol, mannitol, in the market for plastic materials oxalic acid, gluconic acid, acetic acid, and resins, whose composition in the and ethylene. Sorbitol is used to USA (1992) was low-density manufacture vitamin C, for polyethylene (19%), high-density toothpaste, cosmetics, and paints. polyethylene (16%), polyvinyl chloride Mannitol is used to produce polyester or PVC (15%), polypropylene (13%), and plastic foam, and is also used polystyrene (8%), and more than 18 medically as a plasma expander additional materials account for the (Ghosh, 1988; Shuren, 1990). remaining 29% (Beach and Price, 1993). Large-scale, bioprocess technology already has had a significant impact Vegetable adhesives on the use of starch for producing citric and lactic acids. Improved Environmental concerns in the USA fermenting processes have been over synthetic adhesives have spurred developed for producing butyric, new starch-using technologies succinic, and propionic acids (Zeikus, destined mainly for the packaging 1993). market. Starch-based adhesives are usually less expensive than synthetic Food adhesives and are free of the unpleasant odors of some animal Previously, starch was appreciated glues. In 1990, the USA consumed mainly for its nutritional value as a
116 World Production and Marketing of Starch source of calories. Currently, it is also Other uses valued for its functional properties related to human health. For example, Other examples of new or expanded resistant starch, as does fiber, helps markets include systems for stimulate digestion, and plays a role in controlled release of chemicals, the prevention of colon cancer. Fat coating agents, surfactants, substitutes such as maltodextrins and plasticizers, and sequestrants complex carbohydrates help reduce based on starch (Doane, 1993). caloric intake (Koch et al., 1993). Figure 2 divides the potential Other novel starch-based products industrial (nonfood) use of a range include solid glucose and fructose, of new starch-derived products into new combinations of starch and fiber, five categories. Figure 3 and modified maize and cassava summarizes both current and starches used to replace lactic protein future uses of starch-based in processed meat and yogurt. products.
* Binders and glues * Thickeners Auxiliary material Process aids * Texturizers * Formulation aids * Protective colloids
* Polyols * Organic acids Biotechnology Raw materials * Amino acids (fermentation) * Polysaccharides * Enzymes
* Polyethylene and polypropylene Processing of * Polystyrene Starch Functional synthetic * Polyvinyl chloride (PVC) additives polymers * Polyurethane foam * Styrene and butadien lattices
* Polyesters and alkyd resins * Polyurethanes Component Incorporation into * U/F or M/F resins synthetic polymers * Phenolic resins * Grafted polymers
* Surfactants and detergents End product or * Sequestrants Active materials intermediate * Builders product * Perborate boosters * Chiral building blocks
Figure 2. New categories of nonfood industrial uses for starch. (After Koch and Roper, 1988.)
117 Cassava Flour and Starch: Progress in Research and Development
Ethanol Oxygenated motor fuels/solvents/cosmetics/pharmaceuticals
Lactic acid Biodegradable plastics, mold retardant, acidulants
Itaconic acid Plastic objects Fermentation processes Citric, gluconic acids Cleaners, control of metal contaminants Commercial products from Enzymes Catalysts HFCS, denim, ethanol, detergents agricultural materials: Pharmaceuticals Antibiotics, vitamin B12, etc. Acetic acid Acetone n-Butanol Xanthan gum Oil, textiles Glycerol Fumaric acid Fermentation byproducts Dry ice, fuel gas, animal feed Malic acid Succinic acid Oxidation/dehydration Polyester plastics Starch Hydrolysis Glucose Sorbitol/ Plastics/alkyd Hydrogenation Mannitol paints, coatings
Depolymerization with heat, Economical starches with Paper goods, textiles, acids, oxidizing agents improved performance adhesives
Starch with improved resistance Powder for surgical gloves, Crosslinking to shear and temperature other anti-stick products
Reaction with ethylene oxide Hydroxyethyl starch Coated papers
Reaction with Cationic Floculants/fiber Water treatment, paper reactive amines starch modification goods, textiles
Acrylonitrile polymerization Adsorbent Diapers, adsorbent pads, and hydrolysis material seed coats, filters
Figure 3. Current and future starch-based products (with processes in italics). (After Parker, 1993, personal communication.)
References AVEBE. 1989. Potato starch. Foxhol, the Netherlands. 17 p. The advance of sugar’s competitors in perspective. 1991. Int. Sugar Beach, E. D. and Price, J. M. 1993. The effects Sweetener Rep. 123:22, 355-358. of expanding biodegradable polymer production on the farm sector. In: Agra Europe. 1990. Prospects for alternative Industrial uses of agricultural materials. uses of cereals and other crops. Situation and outlook report, no. 6. Agra-Briefing, no. 23. Kent, UK. 35 p. Economic Research Service, United States Department of Agriculture (ERS/ Atthasampunna, P. 1990. Cassava processing USDA), Washington, DC, USA. p. 41-48. and utilization in Thailand. In: Howeler, R. H. (ed.). Proceedings of Cereda, M. P. 1991. General viewpoint of the Third Regional Workshop of the cassava starch industries in Brazil. Cassava Research Network in Asia, Paper presented at the Cassava Starch held Oct. 22-27, 1990, Malang, Workshop, 17-20 June, Centro Indonesia. CIAT, Cali, Colombia. p. Internacional de Agricultura Tropical 315-326. (CIAT), Cali, Colombia. CIAT, Cali, Colombia. (Abstr.)
118 World Production and Marketing of Starch
Christmann, V. 1991. Price formation and Kirby, K. W. 1990. Specialty starches: use in the use of starches in the non-food the paper industry. In: Glass, J. E. area. In: The production and and Swift, G. (eds.). Proceedings of alternative uses of renewable raw the American Chemical Society (ACS) materials from agriculture and Symposium. ACS, Washington, DC, forestry. Research document USA. p. 274-287. prepared for the German Government, Sonderheft, Germany. Koch, H. and Roper, H. 1988. New p. 111-115. (Typescript.) industrial products from starch. Starch/Stärke 4:121-131. Claassen, T. L. and Brenner, K. 1991. A ‘new world order’ for sweeteners? ______; ______; and Hopcke, R. Sugar y Azúcar 86:10, 22-24, 26. 1993. New industrial uses of starch. In: Meuser, F.; Manners, D. J.; and Coutouly, G. 1991. Genie enzymatique. Seibel, W. (eds.). Plant polymeric Masson et Doin, Paris, France. carbohydrates. Royal Society of Chemistry, Cambridge, UK. Damardjati, S. D.; Widowati, S.; and Dimyati, p. 157-179. A. 1990. Present status of cassava processing and utilization in Leuch, D. J. 1990. The effects of the Indonesia. In: Howeler, R. H. (ed.). Common Industrial Policy on the Proceedings of the Third Regional European Community wheat-washing Workshop of the Cassava Research industry and grain trade. Staff report, Network in Asia, Oct. 22-27, Malang, no. AGES 9023. Economic Research Indonesia. CIAT, Cali, Colombia. Service, United States Department of p. 298-314. Agriculture (ERS/USDA), Washington, DC, USA. 26 p. Doane, W. M. 1993. Starch: opportunities for new industrial uses. Cereal Foods Leygue, J. P. 1993. Débouchés industriels World 38(8):613. des céréales. Institut technique des céréales et des fourrages (ITCF), Farris, P. L. 1984. Economics and future of Céréaliers du France, Paris, France. the starch industry. In: 32 p. Whistler, R. L. and Paschall, E. F. (eds.). Starch: chemistry and Long, J. E. 1985. United States markets for technology. Academic Press, Orlando, starch-based products. In: van FL, USA. p. 11-24. Beynum, G. M. A. and Roels, J. A. (eds.). Starch conversion technology. Ghosh, S. P. 1988. Tuber crops. Oxford and Marcel Dekker, Delft, the IBH Publishing, New Delhi, India. Netherlands. p. 335-347.
Higley, N. A. and White, J. S. 1991. Trends in Lynam, J. 1987a. Indonesia, a multi-market fructose availability and cassava economy. In: Lynam, J. The consumption in the United States. cassava economy of Asia: adapting to Food Technol. 10:118-122. economic change. Section 4, draft version. CIAT, Cali, Colombia. 55 p. Hiunok, L. 1993. Ethanol’s evolving role in the U.S. automobile fuel market. ______. 1987b. Thailand, rapid growth In: Industrial uses of agricultural driven by export markets. In: Lynam, materials. Situation and outlook J. The cassava economy of Asia: report, no. 6. Economic Research adapting to economic change. Section Service, United States Department of 7, draft version. CIAT, Cali, Colombia. Agriculture (ERS/USDA), 55 p. Washington, DC, USA. p. 49-54. ______. 1987c. World and Asian markets Jones, S. F. 1983. The world market for for cassava products. In: Lynam, J. starch and starch products with The cassava economy of Asia: particular reference to cassava adapting to economic change. Section (tapioca) starch. Report no. G173. 8, draft version. CIAT, Cali, Colombia. Tropical Development and Research 49 p. Institute (TDRI), London, UK. 98 p.
119 Cassava Flour and Starch: Progress in Research and Development
Malerbe, A. 1990. La chimie verte: quelles ______and Henry, G. 1993. The changing strategies pour les industries du role of cassava in South China’s sucre et de l’amidon. Economie et agro-industrial development: Sociologie Rurales, no. 34. Grignon, problems and opportunities. Paper France. 101 p. presented at the regional seminar on “Upland Agriculture in Asia”, April Marter, A. D. and Timmins, W. H. 1992. 6-8, Regional Coordination Centre for Small-scale processing of sweet Research and Development of Coarse potato in Sichuan Province, People’s Grains, Pulses, Roots, and Tuber Republic of China. Trop. Sci. Crops in the Humid Tropics of Asia 32:241-250. and the Pacific (CGPRT), Bogor, Indonesia. Mitch, E. L. 1984. Potato starch: production and uses. In: Whistler, R. L. and Titapiwatanakun, B. 1993. Thai cassava Paschall, E. F. (eds.). Starch: starch industry: current and future chemistry and technology. Academic utilization. Paper presented at the Press, Orlando, FL, USA. p. 479-489. International Meeting on Cassava Flour and Starch, Jan. 11-15, 1994, Padmaja, G.; Balagopalan, C.; Kurup, G. T.; Cali, Colombia. CIAT, Cali, Colombia. Moorthy, S. N.; and Nanda, S. K. (Abstr.) 1990. Cassava processing, marketing and utilization in India. In: Howeler, USDA (United States Department of R. H. (ed.). Proceedings of the Third Agriculture). 1993a. Industrial uses Regional Workshop of the Cassava of agricultural materials. Situation Research Network in Asia, Oct. and outlook report, no. 6. Economic 22-27, Malang, Indonesia. CIAT, Cali, Research Service (ERS), USDA, Colombia. p. 327-338. Washington, DC, USA. 71 p.
Rhem, S. and Espig, G. 1991. The cultivated ______. 1993b. Sugar and sweetener. plants of the tropics and subtropics. Situation and outlook report, no. 9. Margraf, Germany. 552 p. Economic Research Service (ERS), USDA, Washington, DC, USA. 57 p. Russo, L. J. 1993. The evolution of technology in the fuel ethanol van Den, T.; Palomar, L. S.; and Amestos, industry. Cereal Foods World F. J. 1990. Cassava processing and 38(8):636. utilization in the Philippines. In: Howeler, R. H. (ed.). Proceedings of Sasson, A. 1990. Feeding tomorrow’s world. the Third Regional Workshop of the United Nations Education, Cassava Research Network in Asia, Scientific, and Cultural Organization Oct. 22-27, Malang, Indonesia. CIAT, (UNESCO) and Editorial Reverté, Cali, Colombia. p. 339-354. Barcelona, Spain. 807 p. Whistler, R. L. 1984. History and future Schmitt, H. 1988. Renewable raw materials: expectation of starch use. In: effects on agricultural markets. Whistler, R. L. and Paschall, E. F. Politische Studien 301:39, 609-618. (eds.). Starch: chemistry and technology. Academic Press, Orlando, Shuren, J. 1990. Cassava processing and FL, USA. p. 1-9. utilization in China. In: Howeler, R. H. (ed.). Proceedings of the Third Zeikus, J. G. 1993. Production of organic Regional Workshop of the Cassava acids from fermentation of starch. Research Network in Asia, Oct. Cereal Foods World 38(8):609. 22-27, Malang, Indonesia. CIAT, Cali, Colombia. p. 355-362.
120 SSSESSIONESSIONESSION 3:
PPPHYSICOCHEMICAL STUDIESTUDIESTUDIES OFOFOF FFFLOURSLOURSLOURS ANDANDAND STTTARCHESARCHESARCHES The Role of Common Salt in Maintaining Hot-Paste Viscosity...
CHAPTER 14
THE ROLE OF COMMON SALT IN MAINTAINING HOT-PASTE VISCOSITY OF CASSAVA STARCH
O. Safo-Kantanka* and Rita Acquistucci.**
Abstract Tipples (1982) pointed out that, in wheat starch, these additives affect its The amylographs of starch and flour gelatinization properties. Additives from three cassava varieties were include sugars, syrups, various ions, determined in salt (NaCl) solutions and some bread ingredients. He cited of 0%, 2.5%, 5%, and 7.5% the study of Hester et al. (1956) on the concentrations. The salt increased effect of sucrose on the pasting the pasting and peak viscosity characteristics of several starches. temperatures. Peak viscosity differed They reported that: with variety, and increased with salt in some cases, but was reduced to below (1) The temperature of the initial rise that of the control in others. Salt also in paste viscosity increased for reduced the extent of retrogradation of most starches, indicating a starch, compared with the control. delayed swelling of granules. (2) The temperature of maximum viscosity of starch pastes was Introduction lower than, or did not reach, 95 °C, indicating less swelling of The average Ghanaian housewife granules. knows that, if a family member is late (3) Granules disintegrated less. for the evening meal of fufu, she must (4) The amount of soluble material add salt, pounding it into the cassava diffusing from the granules was paste (or plantain or cocoyam). This less. practice helps prolong the elasticity of (5) Starch gels became less rigid, and, the pounded paste, which otherwise when high sucrose concentrations will harden, and, in some cases, were used, gels did not form. become watery. Bean and Osman (1959) For industrial starches, certain investigated the effect of 10 different additives are often used to modify sugars and syrups on hot-paste starch properties to make them viscosity curves and gel strength of 5% suitable for particular end products. maize-starch paste. The maximum hot-paste viscosity increased slightly during gelatinization with concentrations of sugar as high as * Crop Science Department, University of 20%, but decreased with higher Science and Technology (UST), Kumasi, Ghana. concentrations. Tipples (1982) also ** National Nutrition Institute, Rome, Italy. cites Medcalf and Gilles’s 1966 study
123 Cassava Flour and Starch: Progress in Research and Development on the effect of different salts on showed a one-step slow swelling, had wheat-starch amylograms. They found good cooking qualities. The three that pasting temperature and peak varieties differed in the strength of the temperature progressively increased, bonding forces between granules according to the effects of the classical (Figures 1 and 2). These three varieties - - - lyotropic anion series (SCN , I , NO 3, were used in the present investigation. - - - - Br , Cl , F , SO 4). Except for Na2SO4 and NaF, the salts studied gave The concentrations of NaCl markedly increased starch peak solutions used by Ganz (1965) for viscosities. Even NaCl concentrations wheat were adopted. They were as low as 0.05 M resulted in a 0.43 M, 0.86 M, and 1.29 M, thus significant increase in wheat-starch giving 2.5%, 5%, and 7.5% salt peak viscosity. solutions, respectively. One sample of 35 g (dry basis) of cassava starch was Ganz (1965) found that when a suspension of wheat starch was heated in 2.5% (0.43 M) NaCl solution in a Brabender viscoamylograph, peak 70 viscosity markedly increased. This 60 increase was believed to be a result of an enhanced maintenance of “granule 50 integrity.” That is, the granule swells, 40 or remains intact, over a longer time 30 before fragmenting. The use of salts was therefore suggested as a way of Swelling power 20 regulating starch swelling. 10
Our study accordingly aimed to 0 verify the Ghanaian housewife’s 60 65 70 75 80 85 90 95 practice, and to find agreement with Temperature (°C) the observed effects of additives on Figure 1. The effect of temperature on the starch gelatinization reported in the swelling power of starch from three literature. cassava varieties. ( = cv. 91934; = cv. Ankra; = cv. 30474.)
Materials and Methods 50 A previous study had already examined the swelling power and 40 solubility of three cassava varieties that differed in cooking quality 30 (i.e., mealiness of the cooked root, and elasticity and smoothness of the 20
pounded paste). Solubility (%) 10 Results showed that the three varieties differed in granule swelling 0 characteristics. ‘Ankra’, a good 60 65 70 75 80 85 90 95 cooking variety, showed a two-step Temperature (°C) gradual swelling of granules. But neither the variety 91934, which Figure 2. The effect of temperature on the solubility of starch from three cassava showed a two-step rapid swelling of varieties. ( = cv. 91934; = cv. Ankra; granules, nor the variety 30474, which = cv. 30474.)
124 The Role of Common Salt in Maintaining Hot-Paste Viscosity... dissolved in each solution and the and in Figures 3 and 4, and are standard Brabender procedure discussed below. followed. The flours were also studied in the same way. Pasting temperature
The addition of salt increased pasting Results and Discussion temperature, although the degree of increase varied with variety. These The pasting cycles of the starches and results agree with the findings of flours are presented in Tables 1 and 2 Hester et al. (1956) (see p. 123). This
Table 1. Viscosity changes (using Brabender viscosity units = BU) in starch during gelatinization in the presence of common salt (NaCl).
Variety Salt Pasting Peak temp. Peak Visc. at Visc. Visc. at Visc. conc’n temp. (°C) (°C) visc. 95 °C after 1 h 50 °C after 1 h at 95 °C at 50 °C
Ankra 0 M 74.0 82.0 560 460 260 480 420 0.43 M 75.5 89.0 360 340 150 220 180 0.86 M 74.0 92.0 300 300 160 200 160 1.29 M 79.3 93.5 360 360 200 300 260
91934 0 M 74.0 77.0 500 380 145 280 240 0.43 M 75.5 81.5 460 380 30 50 40 0.86 M 77.0 84.5 500 440 60 90 80 1.29 M 77.8 87.5 560 500 100 140 100
30474 0 M 71.0 85.0 340 290 140 280 260 0.43 M 78.5 92.0 340 270 110 160 120 0.86 M 81.5 95.0 380 380 180 260 200 1.29 M 81.5 95.0 380 380 260 340 280
Table 2. Viscosity changes (in Brabender viscosity units = BU) in flour during gelatinization in the presence of common salt (NaCl).
Variety Salt Pasting Peak temp. Peak Visc. at Visc. Visc. at Visc. conc’n temp. (°C) (°C) visc. 95 °C after 1 h 50 °C after 1 h at 95 °C at 50 °C
Ankra 0 M 66.5 75.5 480 480 160 240 250 0.43 M 72.5 80.0 500 380 70 120 90 0.86 M 74.0 81.5 500 400 80 120 100 1.29 M 78.5 86.0 420 400 120 180 140
91934 0 M 66.5 75.5 380 40 0 0 0 0.43 M 69.5 77.0 390 100 0 0 0 0.86 M 74.0 80.0 420 180 0 0 0 1.29 M 75.5 81.5 400 220 0 0 0
30474 0 M 71.0 78.5 90 60 30 50 50 0.43 M 75.5 87.5 90 80 10 10 10 0.86 M 75.5 84.5 290 170 10 10 10 1.29 M 75.5 86.0 240 190 20 20 20
125 Cassava Flour and Starch: Progress in Research and Development
600 300 cv. 30474 500 250 cv. 30474
400 200
300 150
200 100
100 50
0 0 0 13 14 15 30 60 90 120 150 180
600 Temp. 50 °C Held at 95 °C Held at 50 °C cv. 91934 500 500
400 cv. 91934 400 300 300 200 Viscosity (BU) 100 200
0 Hot-paste viscosity (BU) 100
0 600 cv. Ankra 0 14 15 30 45 60 90 120 150 180 500 600
400 500 cv. Ankra
300 400
200 300
100 200
0 100 Time 0 14 15 30 45 60 90 120 150 180 (in minutes) 0 Time 0 14 15 30 45 60 90 120 150 180 (in minutes) Temp. 50 °C Held at 95 °C Held at 50 °C Temp. 50 °C Held at 95 °C Held at 50 °C
Cooking temperature and time Cooking temperature and time
Figure 3. The effect of different salt concentrations Figure 4. Effect of different salt concentrations on hot-paste viscosity of starch from on hot-paste viscosity of flour from three cassava varieties. (Salt three cassava varieties. (Salt concentrations: = control; = 7.5%; concentrations: = control; = 7.5%; = 5%; = 2.5%.) = 5%; = 2.5%. means that the salt caused a delay in found similar results when they granule swelling. examined the effect of different salts on wheat starch amylographs. In all three varieties, adding salt also increased the temperature at Peak viscosity which peak viscosity was attained. For example, in ‘30474’, peak The effect of salt concentrations on viscosity of its starch in 5% and 7.5% peak viscosity varied with variety. In salt solutions occurred at 95 °C. The the flours and starches of ‘30474’ and cited Medcalf and Gilles study (1966) ‘91934’, salt concentrations of 5% and
126 The Role of Common Salt in Maintaining Hot-Paste Viscosity...
7.5% resulted in increases in peak syneresis, or the release of water. viscosity. These results agree with Retrogradation is heavily influenced findings by Medcalf and Gilles (1966) by the amylose content of the starch. and Ganz (1965), who found that It declines when salt is added. NaCl concentrations of 0.05 M and Hence, the Ghanaian housewife, by 0.43 M significantly increased peak pounding salt into the pounded paste, viscosity in starches, for which Ganz is reducing its tendency to retrograde, (1965) postulated the “granule thus extending its “table-life.” integrity” hypothesis (p. 124). In ‘Ankra’, results were slightly different: For the three varieties, the extent peak viscosity of untreated starch of retrogradation in pure starch and was far higher than those with salt flour tended to increase as the salt added, even though peak viscosity concentration increased, but, except increased with salt concentration. for starch from cv. 30474, the extent of retrogradation was always less For flour made from ‘Ankra’, the than the control. The cited study by highest salt concentration of 7.5% Hester et al. (1956) also found that had the lowest peak viscosity. Again, starch gels became less rigid when this contrasted markedly with the sucrose was added and that, when behavior of the other two varieties. high sucrose concentrations were used, gels did not form at all. Our results seem to demonstrate that, if starch granules are fragile when swollen, as for variety 91934, Acknowledgments adding NaCl may reduce the fragility, but in other cases, as with ‘Ankra’, This work was undertaken as part salt may inhibit granule swelling. of a contract (Research Contract Number GHA 5416) with the Salt also affected the International Atomic Energy Agency temperatures at which peak viscosity (IAEA). The award of a six-month could be maintained: at temperatures fellowship, which enabled the senior higher than 95 °C peak viscosity author to travel to Rome to carry out would begin to drop. For all three this research, is gratefully varieties, even though adding salt did acknowledged. not increase peak viscosity, compared with the control, no differences existed between peak viscosity and References viscosity at 95 °C. The reason may be that either the salt increased the Bean, M. M. and Osman, E. M. 1959. temperature at which peak viscosity Behaviour of starch during food was attained, or it enabled the preparation. II. Effects of different swollen granules to remain intact for sugars on the viscosity and gel strength of starch pastes. Food Res. a longer time before fragmenting. 24:665.
Retrogradation Ganz, A. J. 1965. Effect of sodium chloride on the pasting of wheat starch granules. Cereal Chem. 42:429. “Retrogradation” is an increased rigidity in the starch gel that occurs Tipples, K. H. 1982. Uses and applications. as starch granules re-associate Brabender.viscoamylograph during cooling, sometimes leading to handbook, 1982.
127 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 15
AMYLOGRAPHIC PERFORMANCE OF CASSAVA STARCH SUBJECTED TO EXTRUSION COOKING1
Z. González and E. Pérez*
Introduction Materials and Methods
In Venezuela, cassava (Manihot A commercial cassava starch was esculenta Crantz) is consumed submitted to extrusion cooking in two preferably fresh but also in other Rheocord Torque Rheometers. Model forms. During 1991, 381,069 t of 104 had a single rotating screw that cassava were produced, of which operated at 90 rpm at a temperature 183,913 t were used for human of 150 °C, with a 25% sample consumption, including 19,549 t for moisture content. Model 3000 had producing “casabe,” a type of cassava double, co-rotating screws that also bread. Another 38,107 t were used operated at 90 rpm, but at for animal feed, 244 t for export. temperatures of 100 and 150 °C, and About 152,428 t were estimated as with 10%, 21%, and 25% sample lost (INN, 1991). moisture contents.
Because starch has multiple uses Starch suspensions at 6.88% in the food, pharmaceutical, oil, and (w/w dry basis) were prepared. These textile industries, great interest has were heated at a rate of 1.5 °C per arisen in the use of alternative, minute in the bowl of a Brabender low-cost sources of this amylograph (model A.V. 40, 60-cycle), polysaccharide. Starch’s functional from 30 until 90 °C. Suspensions properties can be modified by were maintained at this temperature different methods. Our study for 30 min and then cooled at the evaluated the effect of extrusion same rate to 50 °C, at which they cooking on the amylographic were maintained for 30 min more. performance of cassava starch. Water absorption capacity, solubility, and swelling power of both extruded and native starches were determined by Schoch’s method (1964).
Results
* Instituto de Ciencia y Tecnología de Table 1 shows the most important Alimentos, Facultad de Ciencias, Universidad parameters of the amylograms Central de Venezuela (UCV), Caracas, Venezuela. obtained. The initial gelatinization temperature of starches extruded at 1. No abstract was provided by the authors. 25% moisture content (61.5 °C) and
128 Amylographic Performance of Cassava Starch Under Extrusion Cooking
Table 1. Effect of extrusion cooking on the most important parameters used in cassava starch amylography.
Parametera Sample
Native Extruded Extruded Extruded starch starchb starchc starchd
Initial gelatinization temperature (°C) 60.8 61.5 55.5 61.5 Final gelatinization temperature (°C) 70.5 77.5 67.5 78.0
Maximum viscosity (Vmax); (BU) 900 740 860 700
Vmax temperature (°C) 69.8 77.3 66.8 76.5 Viscosity at 90 °C (BU) 380 520 410 530 Viscosity after 30 min at 90 °C (V90/30); (BU) 40 300 260 290 Viscosity at 50 °C (V50); (BU) 400 480 420 320 Viscosity after 30 min at 50 °C (BU) 420 480 430 380
Stability (Vmax - V90/30); (BU) 660 440 600 410 Sedimentation (V50 - V90/30); (BU) 160 180 160 30
Consistency (V50 - Vmax); (BU) -500 -260 -440 -380 a. BU = Brabender viscosity units. b. Single-screw, 150 °C, 25% moisture content, and 90 rpm. c. Double-screw, 100 °C, 10.21% moisture content, and 90 rpm. d. Double-screw, 150 °C, 25% moisture content, and 90 rpm.
that for native starch (60.8 °C) did not All processed samples had lower differ significantly. However, initial maximum viscosity (Vmax) values gelatinization temperature for the (Table 1) compared with native sample extruded at 10.21% moisture starches (900 Brabender viscosity content by the double-screw extruder units [BU]). Starches extruded at was 55.5 °C. Apparently, the 25% moisture content by single-screw conditions under which this last extruders showed Vmax of 740 BU and operation was performed favored the by double-screw extruder, 700 BU. access of water to the amorphous These values were lower than that for zones of the starch granules, causing starch extruded at 10.21% moisture them to swell faster. Gelatinization content by a double-screw extruder, therefore began at a lower which, in its turn, differed by 40 BU temperature. from that of native starch (860 BU).
The interval between initial and Maximum viscosities of extruded final gelatinization temperatures was starches, at 25% moisture content, greater in starches extruded at 25% were obtained at 77.3 (single-screw moisture content by both single- and extruder) and 76.5 °C (double-screw double-screw extruders (about 16 °C) extruder), higher than that than those corresponding to starch corresponding to native starch processed by the double-screw (69.8 °C) (Table 1). Starch extruded extruder at 10.21% moisture content at 10.21% moisture content by the (12 °C) and to native starch (9.7 °C) double-screw extruder not only (Table 1). These results indicate that showed the lowest temperature for extrusion partially transformed the Vmax (66.8 °C), but also the lowest starch granule structure and affected gelatinization temperature range the macromolecules. This caused a (55.5-67.5 °C). This finding probably greater temperature interval in indicates that, because the extrusion extruded products than in native process makes more water available starches. to the amorphous zones of starch
129 Cassava Flour and Starch: Progress in Research and Development granules, gelatinization advanced These findings suggest that the more rapidly and so reached Vmax at a expansion corresponding to Vmax of lower temperature. extruded starches was the result of various factors acting together,
Because no Vmax value similar to principally swelling power and that of native starch was obtained in solubility. The greatest value of Vmax the samples processed, a certain of extruded samples thus degree of macromolecule rupture corresponded to processed starch at and/or reorganization can be 10.21% moisture content in the inferred. Although native starch double-screw extruder, whose presented the highest Vmax, its swelling capacity was the highest of swelling power was not the highest the starches tested. Extruded (Table 2). Also, at about 70 °C, the starch at 25% moisture content in temperature at which Vmax of native the single-screw extruder had, starch was obtained, the highest overall, the lowest solubility values value of water absorption (24.31 g/g of the starches, even though it starch) and of swelling power tended to swell less than the (2.34 g/g starch) corresponded to starches processed by the extruded starch at 10.21% moisture double-screw extruder. content by the double-screw extruder (Table 2).
Table 2. Effect of extrusion cooking on water absorption, solubility, and swelling power of cassava starches.
Temperature (°C) Sample
Native Extruded Extruded Extruded starch starcha starchb starchc
Water absorption (g/g starch) 65 2.40 7.40 0.90 0.89 70 15.04 14.46 24.31 19.09 75 23.22 17.74 23.14 - 80 29.47 21.09 29.41 24.27 85 31.77 25.17 37.95 28.49 90 43.41 27.86 38.93 30.41
Solubility (%) 65 1.90 5.44 9.21 9.11 70 11.48 11.09 17.42 17.50 75 21.57 13.52 16.23 - 80 22.11 16.88 22.20 21.78 85 25.21 19.52 39.79 26.33 90 33.09 21.79 59.87 26.54
Swelling power 65 0.50 0.83 0.90 0.86 70 0.83 1.54 2.34 1.90 75 1.15 1.80 2.24 - 80 1.29 2.19 2.78 2.32 85 1.53 2.62 3.48 2.66 90 2.04 2.93 3.28 2.55 a. Single-screw, 150 °C, 25% moisture content, and 90 rpm. b. Double-screw, 100 °C, 10.21% moisture content, and 90 rpm. c. Double-screw, 150 °C, 25% moisture content, and 90 rpm.
130 Amylographic Performance of Cassava Starch Under Extrusion Cooking
Starch modified at 25% moisture difference between the viscosity at content in the double-screw extruder, 50 °C and that after 30 min at 90 °C despite showing an intermediate (Rasper, 1980). Native starch and swelling ability compared with the starch extruded at 10.21% moisture rest of the processed samples, had content by the double-screw extruder the lowest Vmax. The reason may have presented the same retrogradation been that its solubility was usually tendency (160 BU), and starch higher at the same moisture content processed by the single-screw than that of the single-screw extruder extruder at 25% moisture content (Table 2). showed the greatest sedimentation (180 BU). The lowest value for this In summary, extrusion tended to index corresponded to starch reduce water absorption capacity and extruded at 25% moisture content by solubility of samples processed at the double-screw extruder (30 BU). 25% moisture content by single- and double-screw equipment, whereas the Viscosity after 30 min at 50 °C swelling power of all extruded was higher than viscosity at 50 °C, starches increased. However, in except for starch extruded by the starch processed at 10.21% moisture single-screw extruder, whose value content by the double-screw extruder, remained constant (480 BU). In solubility tended to increase. general terms, all starches showed stability during cooking at 50 °C. Without exception, all starches had reduced viscosity values at 90 °C Consistency (the difference in relation to Vmax and, after 30 min at between viscosity at 50 °C and Vmax; 90 °C, in relation to the initial Rasper, 1980) increased as a viscosity (Table 1). The different consequence of the extrusion process. starch suspensions showed low Native starch showed a value of stability during cooking, that is, -500 BU, while extruded starches granules were highly susceptible to showed values of -440 BU (starch shearing stress. This was reflected in extruded at 10.21% moisture content the positive values of the stability by a double-screw extruder), -260 BU index, which is defined as the (starch extruded by a single-screw difference between Vmax and viscosity extruder), and -380 BU (starch after 30 min at 90 °C (Rasper, 1980). extruded at 25% moisture content by Native starch was the least stable a double-screw extruder). during cooking (660 BU), followed by starch extruded at 10.21% moisture content in the double-screw extruder Conclusions (600 BU), starch processed at 25% moisture content in single-screw Extrusion cooking of cassava starch extruder (440 BU), and starch caused a series of modifications in the processed in the double-screw starch structure, depending on extruder (410 BU). cooking conditions. The amorphous zones of starch extruded at 10.21% Viscosity values at 50 °C of all moisture content by the double-screw starches were higher than the extruder apparently had greater corresponding viscosity values after access to water. This translated into 30 min at 90 °C. This finding quicker swelling of starch granules suggests that a certain degree of and the start of gelatinization for all retrogradation occurred in these extruded samples at a lower starches, which could be quantified temperature, although the intervals of as a sedimentation index, or the gelatinization temperature increased
131 Cassava Flour and Starch: Progress in Research and Development due to the process. Swelling power, Rasper, V. 1980. Theoretical aspects of stability, and consistency of extruded amylographology. In: Shuey, W. C. starches also increased, while V and Tipples, K. H. (eds.). The max amylograph handbook. American decreased. This appeared to depend Association of Cereal Chemists, St. principally on swelling power and Paul, MN, USA. p. 1-6. solubility, among other factors. In the sample processed at 25% Schoch, T. J. 1964. Swelling power and moisture content by the double-screw solubility of granular starches. In: Whistler, R. L. (ed.). Methods in extruder, the tendency of starch carbohydrate chemistry, vol. 4. retrogradation was notably reduced. Academic Press, New York, USA. p. 106-108.
References
INN (Instituto Nacional de Nutrición). 1991. Hoja de balance de alimentos, versión preliminar. Caracas, Venezuela.
132 Improving the Bread-Making Potential of Cassava Sour Starch
CHAPTER 16
IMPROVING THE BREAD-MAKING POTENTIAL OF CASSAVA SOUR STARCH
D. Dufour*, S. Larsonneur*, F. Alarcón**, C. Brabet*, and G. Chuzel***
Abstract Introduction
Cassava sour starch, fermented for Cassava sour starch is a product of use in bread making, is traditionally traditional rural industry in Latin sun-dried. Changes in the America. It is used for making breads physicochemical and functional such as pandebono and pan de yuca properties of the starch during in Colombia, and pão de queijo in sun-drying were examined for Brazil; and for industrially processed correlations between these changes snack foods (Cereda, 1973, 1991; and the starch’s bread-making Cereda and Nuñes, 1992; Chuzel, potential. Starch samples collected 1990). Urban markets for sour starch after fermentation and drying were are growing in Brazil (where it is analyzed for their pH, total acidity, known as polvilho azedo) and in and lactic acid. Viscoamylograms Colombia (almidón agrio). were plotted and bread-making potential determined. Results Bakers and manufacturers indicated that exposure to sunlight regard swelling power as the main considerably changes the criterion of quality, but this is often physicochemical and rheological unpredictable. Our study aimed to properties of cassava sour starch, understand how bread-making correlating directly with potential is increased during bread-making potential. During traditional processing, so we could oven-drying, the lactic acid content suggest ways of achieving a better remained steady, whereas sun-drying quality sour starch (Chuzel and at a similar temperature greatly Muchnik, 1993). reduced it, thus augmenting the cassava sour starch’s bread-making The traditional method consists of potential. wet-process extraction of starch from cassava roots (Pinto, 1978; Ruiz, 1988, 1991). The starch is then stored in 0.5 to 5-t capacity tanks and * CIRAD/SAR, stationed at the Cassava fermented for 20 to 60 days, according Utilization Section, CIAT, Cali, Colombia. to climatic conditions (temperatures ** CIRAD/SAR, Montpellier, France. may range from 15 to 25 °C) (Jory, *** CIRAD/SAR, stationed at the Faculdade de 1989). Lactic fermentation takes place Ciências Agronômicas (FCA), Universidade Estadual Paulista (UNESP), São Paulo, and the starch pH drops to about Brazil. 3.5-4.0 (Cárdenas and de Buckle,
133 Cassava Flour and Starch: Progress in Research and Development
1980). It is then sun-dried on Our study examines how sunlight drying tables (Brazil) or on black changes the bread-making potential of plastic sheeting laid on the ground cassava sour starch by changing the (Colombia). following physicochemical and rheological properties: pH, total Both fermentation and acidity, lactic acid content, and sun-drying give the cassava starch Brabender viscosity. The important its bread-making potential (Chuzel, role of lactic acid is also 1992). Fermentation also causes demonstrated. substantial modifications to the starch’s organoleptic and physicochemical characteristics Materials and Methods (Camargo et al., 1988; Cereda, 1985; Nakamura and Park, 1975). Preparing samples
Larsonneur (1993) achieved Starch samples were collected from optimal swelling power by exposing production units at Santander de thin layers (0.5 to 1 cm) of sour Quilichao (Department of Cauca, starch to the sun (solar radiation Colombia). Three local cassava intensity ≈1,200 W/m2) on sheets of cultivars were used: ‘Amarga’ (referred black plastic, and shaking the to as starch A), ‘CMC 40’ (B), and sheets frequently. In confirmation, ‘Algodona’ (C). Colombian sour starch producers maintain that drying in low levels of Extracted starch was left to sunlight results in poor-quality sour ferment in tiled tanks (0.95 x 0.82 x starch with low bread-making 0.79 m, capacity 0.5 m3). The average potential. Brazilian large-scale temperature in the zone was 20 °C, manufacturers prefer drying sour with a small day-night variability of starch in the sun (sometimes using 18 to 22 °C. For starch A, a sample of 12 km of drying tables) to the starch milk (unfermented starch various types of driers (e.g., hot air, suspension in water) was collected flash driers, and drum driers) used immediately after extraction. A for producing unfermented cassava sample of fermented starch was taken starch. Industrial trials have shown after 30 days of fermentation, just that sour starch dried artificially before farmers typically initiate has no significant swelling power. sun-drying. The samples were then transferred, in an insulated box, to the Sour starch is the main CIAT laboratory, frozen at -20 °C, and ingredient (mixed with fats or subjected to drying tests and analysis. cheese, eggs, and salt) in traditional, high-swelling breads. Drying conditions Such breads contain no wheat flour, nor do they undergo yeast Sun-drying, on black plastic sheets for fermentation before baking. 8 h, was similar to traditional sour Additives are not used and the starch-drying conditions in Colombia dough is baked immediately after (layer 1 to 1.5 cm thick, with agitation kneading, with no rising or every 2 h). “proofing” time. Rising, therefore, does not involve a protein-gluten Exposure to sun network nor the production of carbon dioxide by yeasts as seen in, Starch samples were sun-dried for for example, the making of French different lengths of time (2, 4, 6, and bread (Godon, 1981). 8 h) and then oven-dried at 40 °C to a
134 Improving the Bread-Making Potential of Cassava Sour Starch final moisture content of about 11%. temperature was kept constant for A control sample was oven-dried only, 10 min. Viscosities are expressed in at 40 °C. This temperature was Brabender units (BU). chosen because it does not cause gelatinization, but is representative of Measurement of pH. A 10% (w/v) an average daytime temperature in aqueous suspension was agitated at strong sunlight. The sampling plan ambient temperature (20 ± 2 °C) for was as follows: 30 min and then centrifuged at 15,000 g for 15 min. Supernatant pH was measured. Moist starch Dry starch
0 2 4 6 8 Assay of total acidity. Total acidity was assayed in 50 ml of hours of drying the supernatant described above by titration of a NaOH 0.1 N S______S solution in the presence of 1% S______S phenolphthalein-alcohol solution. The results were measured in moles of acid S______S per gram of dry weight of sour starch.
S______S Assay of lactic acid. Cassava sour starch (10 g) was added to S 15 ml H2S04 (0.006 M) and agitated for 1 min. The suspension was where: homogenized for 1 min at 24,000 rpm S = sampling for in an Ultraturrax blender, agitated subsequent analysis in a vortex mixer for 1 min, and = sun-drying centrifuged at 9,800 g for 25 min. ______= oven-drying The supernatant was passed through a 0.45 m filter and analyzed by high-performance liquid Rheological and physicochemical chromatography (HPLC) as follows: of analyses the filtrate, 20 µl was injected into an Aminex HPX87H column (Biorad), Each of the following analyses was which was controlled thermostatically performed in duplicate on starches A, at 65 °C. Column separation was B, and C: based on a combination of ion exchange, molecular screening, and Viscoamylograms. The hydrophobic exchange. A solution of rheological properties were determined H2S04 (0.006 M) was used as eluant at by using a Brabender a flow rate of 0.8 ml/min (Giraud and viscoamylograph. The sour starch Raimbault, 1991). The lactic acid was first ground and sieved through a peak was detected under ultraviolet 65/cm ( ≈150 µm) mesh. An aliquot light at 210 nm. The results were (500 ml) of an aqueous sour-starch expressed in grams of lactic acid per suspension (5% dry matter) was used 100 g of initial sour-starch dry weight. to plot the viscoamylogram. The analysis unit rotated at 75 rpm; the Measuring bread-making temperature of the reaction mixture potential. Procedures for bread increased steadily at 1.5 °C/min from making with sour starch and 25 to 90 °C. The mixture was kept evaluation of swelling power were at 90 °C for 20 min, then steadily developed by Escobar and Molinari cooled at 1.5 °C/min to 50 °C; this (1990) and modified by Laurent (1992)
135 Cassava Flour and Starch: Progress in Research and Development and Larsonneur (1993). Sour starch (Larsonneur, 1993). The samples was ground in a mortar and sieved for taken after fermentation were therefore 10 min through a 65/cm (≈150 µm) frozen to be sun-dried the following mesh. Of this fraction, 85 g (dry day. weight) was mixed with 100 g of Colombian cheese (Campesino, brand The viscoamylograms in Figure 1 “Alpina”) in a Hobart kneading show the performances of two machine operated at low speed subsamples taken from the original (165 rpm) for 1 min. Water was added starch sample A. One subsample was to obtain a total of 65 ml of water in frozen and the other fermented for the dough. It was then kneaded at 33 days. They were then sun-dried medium speed (300 rpm) for 2 min. under identical conditions. The Six 30-g rings of dough with an inside viscoamylograms reveal considerable diameter of 2 cm were prepared. These modification of the rheological were baked at 280 °C for 17 min and properties of the fermented sour starch. cooled for 2 h at ambient temperature. Each loaf was weighed and its volume Pasting temperature (62.5 °C) and measured with a volumeter according that of maximum viscosity (70 °C) to Vanhamel et al. (1991). The specific were identical in all the samples. The volume of the bread was then tendency toward retrogradation (a expressed in cm3/g. decrease in viscosity after the peak) increased relative to fermentation, a finding which agrees with those of Results and Discussion Nakamura and Park (1975). Peak viscosity decreased in relation to Previous tests had shown that freezing the time allowed for the had no effect on the viscoelastic fermentation—bacterial amylases to properties of starch or on the break down the large starch molecules bread-making potential of sour starch (Camargo et al., 1988).
400
300 70 °C
200 Viscosity (BU)
100
62.5 °C
0 0 20 40 60 80 100 Analysis time (minutes)
Figure 1. Changes in the rheological properties of starch, extracted from cassava variety ‘Amarga’, during fermentation. The samples were sun-dried for 8 h before analysis. ( = unfermented starch; = starch fermented 33 days.)
136 Improving the Bread-Making Potential of Cassava Sour Starch
The specific volume of the loaves the two latter viscoamylograms are increased from 3.5 to 6.5 cm3/g for similar, indicating that oven-drying starch A, from 2.0 to 5.8 cm3/g for B, barely affects the physicochemical and from 1.9 to 5.2 cm3/g for C. properties of sour starch. The sun-dried starch shows a strong The effect of sunlight retrogradation tendency and a notable decrease in maximum viscosity (from Direct exposure to sunlight (8 h under 320 to 220 BU). equatorial conditions) caused substantial changes in the rheological Analysis of pasting properties of properties of fermented starch A. The starch A after 0, 2, 4, 6, and 8 h of viscoamylogram (Figure 2) differs sun-drying reveals a rapid increase in widely from those of the same starch retrogradation tendency after about analyzed before drying (wet starch) and 3 h of exposure to sunlight (Figure 3). after oven-drying at 40 °C. In addition, In contrast, the decrease in maximum
400
300
200 Viscosity (BU) 100
0 0 20 40 60 80 100 Analysis time (minutes)
Figure 2. Influence of type of drying on the rheological properties of starch extracted from cassava variety ‘Amarga’. Samples were taken after 33 days of fermentation. ( = wet starch; . . = starch oven-dried 8 h; = starch sun-dried 8 h.)
400
300
200 Viscosity (BU) 100
0 0 20 40 60 80 100 Analysis time (minutes)
Figure 3. Influence of sun-drying time on the rheological properties of starch extracted from cassava variety ‘Amarga’. Samples were taken after 33 days of fermentation. ( = wet starch; = starch sun-dried 2 h; = starch sun-dried 4 h; = starch sun-dried 6 h; = starch sun-dried 8 h.)
137 Cassava Flour and Starch: Progress in Research and Development viscosity is linear (r2 = 0.934) against 7 time of exposure to sunlight within the 6 0 to 8-h range (Figure 4). Because 5 /g)
maximum bread-making potential was 3 attained after 3 h of sun-drying 4 (Figure 5), bread-making potential (cm appears to relate more directly to the Specific volume 3 increase in retrogradation tendency of 2 starch. 012345678910 Sun-drying time (hours) In addition, when oven-dried, the Figure 5. Changes in bread-making potential of same starch showed no increase in starch extracted from cassava variety bread-making potential. Sun-drying ‘Amarga’ in relation to duration of kinetics observed for other cassava sun-drying. cultivars (starches B and C) are shown in Figure 6. They confirm that bread-making potential is acquired during exposure to solar radiation and not after oven-drying. 7 6 Significantly, the pH of starch A 5
(sampled after 33 days of /g) 3 4 fermentation) rose from 3.45 to 3.70 after sun-drying and increased to only (cm 3
3.50 when oven-dried (Figure 7). Specific volume 2 Starches B and C similarly increased 1 in pH during sun-drying from 3.48 to 012345678910 3.55 (B) and from 3.45 to 3.55 (C) Drying time (hours) (Table 1). Because the pre-drying pH Figure 6. Changes in bread-making potential of 3.45 corresponded to the pKa of of starches extracted from cassava lactic acid, the medium would have varieties ‘Amarga’ ( ) ‘CMC 40’ ( ), been strongly buffered, with lactic and and ‘Algodona’ ( ) in relation to duration of sun-drying. All three lactate forms in equal proportions. varieties were also oven-dried This small increase in pH during ( ; oven-dried ‘CMC 40’ ). sun-drying (0.25 unit, from 3.45 to
340 3.80
320 y = 316.60 - 11.60 x r2 = 0.934 3.75 300 3.70 3.65 280 (BU) 3.60 260 pH 3.55 240
Maximum viscosity 3.50 220 01 234 5 678 3.45 3.40 Sun-drying time (hours) 012345678 Drying time (hours) Figure 4. Changes in maximum viscosity of starch extracted from cassava variety Figure 7. Changes in the pH of starch extracted ‘Amarga’ in relation to duration of from cassava variety ‘Amarga’ in sun-drying. Samples were taken after relation to drying time ( = sun-drying; 33 days of fermentation. = oven-drying).
138 Improving the Bread-Making Potential of Cassava Sour Starch
Table 1. Acquisition of bread-making potential during fermentation.
Starch Cassava varietya ABC pH of wet sweet starch 6.8 - - pH of sour starch before sun-drying 3.45 3.48 3.45 pH of sour starch after sun-drying 3.70 3.55 3.55
Bread specific volume (ml/g) of oven-dried starch 3.5 2 1.9
Bread specific volume (ml/g) of sun-dried starch 6.5 5.8 4.7
Total acidity before sun-drying (10-5 mol/g dry matter) 10.5 10.4 7.7
Total acidity after sun-drying (10-5 mol/g dry matter) 6.8 9.4 6.7
Lactic acid before sun-drying (10-6 mol/g of dry matter) 105 105 76
Lactic acid after sun-drying (10-6 mol/g of dry matter) 68 94 66
a. A = ‘Amarga’; B = ‘CMC 40’; C = ‘Algodona’.
3.70, starch A) therefore suggests 10.4 to 9.4 x 10-5 and 7.7 to considerable variation in the 6.7 x 10-5 mol/g dry weight, proportions of lactic acid and lactate, respectively. The greater fall in the considering the chemical equation of lactic acid content of starch A (35% the buffer solutions (pH = pKa + log against 10% and 13%, respectively) base/acid). and its higher bread-making potential (6.5 against 5.8 and 4.7, respectively) This variation during sun-drying correlate well (Table 1). The can be interpreted either by the differences observed between starches transformation of lactic acid into A, B, and C may be heightened by the lactate or by the disappearance of the diversity of cultivars used, a finding lactic form. The lactic acid assay of fermented starch sample A (Figure 8), 110 sun-dried and oven-dried, indicates that the initial (lactic acid + lactate) 100 content was 10.5 x 10-5 mol/g dry mol/g) 90 weight, which corresponds to the -6 conversion of 1% of the initial starch 80 into lactic acid during fermentation. This decreased to 6.8 x 10-5 mol/g dry 70 content (10 weight (a decrease of 35%) during Lactic acid + lactate 60 sun-drying but remained unchanged 01 2345678 during oven-drying for 8 h. Because Drying time (hours) the oven-drying temperature was similar to that of sun-drying, the Figure 8. Changes in the lactic acid content disappearance of lactic acid cannot be of starch extracted from cassava variety ‘Amarga’ in relation to drying ascribed to volatilization. Starches B time ( = sun-drying; = oven-drying). and C similarly produced decreases of
139 Cassava Flour and Starch: Progress in Research and Development which agrees with that of Chuzel content decreased by as much as (1992). 35% during sun-drying only, suggesting a photochemical reaction The pH increase suggests that involving the starch, resulting in the lactic acid is consumed in a chemical formation of a three-dimensional reaction during sun-drying. The network that retains gas bubbles HPLC method used did not permit during baking and, hence, assay of combined forms of lactic acid accounting for the acquisition of and thus did not detect polymerized bread-making potential by sour forms or covalent bonds which might starch. have formed during drying. Detection would be possible after total Characterization of the solar hydrolysis of the starch. radiation involved in this process should lead to the design of drying In classic bread making, wheat apparatus that would combine both gluten forms a three-dimensional air-drying and radiation. Such a network that retains gas bubbles system would overcome dependence during baking. Baking additives on climate, reduce labor costs and (xanthan gums) are added to drying space, and reduce losses to non-panifiable flours to increase their wind, poor handling, and external bread-making potential (Eggleston, contamination. Brazilian 1992; Godon, 1981). Because starch industrialists favor developing an is the only significant macromolecule artificial drier to manufacture in sour starch (no protein or cellulose high-quality industrial sour starch. is present), a three-dimensional network may be formed by a A better understanding of the photochemical reaction involving phenomena described in this study lactic acid and fermented starch. should permit the development of Such a network may account for the modified cassava starch with a high acquired bread-making potential of bread-making potential. Such sun-dried cassava sour starch. modified starch could be used as an additive (as are xanthan gums) to improve the bread-making capacity of Conclusions and Prospects flours which expand little. Furthermore, modified cassava starch Fermentation and sun-drying clearly could have great potential for the played a role in obtaining sour starch development of gluten-free bread. with high swelling power and desirable organoleptic characteristics. Good fermentation practice and At the end of fermentation, the pH solar drying, combined with the use was 3.45, following conversion of of cassava cultivars specifically about 1% of the initial starch to lactic chosen for sour starch production, acid. Fermentation gave the starch should facilitate the production of the necessary physicochemical high-quality cassava sour starch for properties required to later achieve which demand exists in bread bread-making potential through making and various industries. exposure to sunlight. Fermentation and sun-drying modified the rheological properties of the starch Acknowledgments and produced a more marked retrogradation and lower maximum The authors thank Marney Pascoli viscosity, together with an increased Cereda (UNESP, Botucatu, Brazil) for swelling power. The lactic acid her advice, hospitality, and access to
140 Improving the Bread-Making Potential of Cassava Sour Starch her extensive knowledge of cassava Chuzel, G. 1990. Cassava starch: current sour starch. and potential use in Latin America. Cassava Newsl. (Cent. Int. Agric. Trop.) 15(1):9-11. The research used facilities at CIAT’s Cassava Quality and ______. 1992. Amélioration technique Utilization Section, and was funded et économique du procédé de fabrication de l’amidon aigre de by CIAT, CIRAD/SAR, and the manioc. In: D. Dufour and European Unión. D. Griffon (eds.). Amélioration de la qualité des aliments fermentés Special thanks go to Alba Lucía à base de manioc: Rapport Chávez and Jorge Mayer, of CIAT’s final du contrat CEE/STD2 TS2A-0225. CIRAD, Montpellier, Biotechnology Research Unit, and France. Luc Laurent, of Université Technologique de Compiègne, ______and Muchnik, J. 1993. La Compiègne, France, for their active valorisation des ressources techniques locales: L’amidon participation in the trials. aigre de manioc en Colombie. In: J. Muchnick (ed.). Alimentation: Techniques et innovations dans References les régions tropicales. Editions L’Harmattan, Paris, France. p. 307-337. Camargo, C.; Colonna, P.; Buleon, A.; and Richard-Molard, D. 1988. Eggleston, G. 1992. Can we make a Functional properties of sour marketable cassava bread cassava (Manihot utilissima).starch: without wheat? Cassava Newsl. polvilho azedo. J. Sci. Food Agric. (Cent. Int. Agric. Trop.) 16(1):7-8. 45:273-289. Escobar, C. A. and Molinari, J. E. 1990. Cárdenas, O. S. and de Buckle, T. S. 1980. Obtención de parámetros para la Sour cassava starch production: a evaluación de la calidad de un preliminary study. J. Food Sci. almidón agrio de yuca. B.S. 45:1509-1512, 1528. thesis. Plan de Estudios de Ingeniería Química, Universidad Cereda, M. P. 1973. Alguns aspectos sobre a del Valle, Cali, Colombia. 75 p. fermentação da fécula de Giraud, E. and Raimbault, M. 1991. mandioca. Ph.D. dissertation. Utilización de la cromatografía Faculdade de Ciências Médicas e líquida de alta resolución (HPLC) Biológicas, Universidade Estadual para la caracterización Paulista, Botucatu, SP, Brazil. 89 p. bioquímica de la fermentación del almidón de yuca. In: [Proceedings ______. 1985. Avaliação da qualidade da of the workshop on] “Avances fécula fermentada comercial de sobre Almidón de Yuca” held at mandioca (polvilho azedo). CIAT, Cali, Colombia, 17-20 June I. Características viscográficas e 1991. (Abstr.) absorção de agua. Rev. Bras. Med. 3(2):7-13. Godon, B. 1981. Le pain. Pour la Science 50:74-87. ______. 1991. Technology and quality of Jory, M. 1989. Contribution à l’étude de sour starch. In: [Proceedings of the deux processus de transformation workshop on] “Avances sobre du manioc comportant une phase Almidón de Yuca” held at CIAT, Cali, de fermentation: Le gari au Togo, Colombia, 17-20 June 1991. (Abstr.) l’amidon aigre en Colombie. Mémoire de mastère en ______and Nuñes, O. L. S. 1992. technologie alimentaire régions Brazilian fermented cassava starch. chaudes. Ecole nationale I. Production and use. In: XVIth supérieure des industries International Carbohydrate agricoles et alimentaires (ENSIA) Symposium held in Paris, France, and CIRAD, Montpellier, France. July 5-10, 1992. (Abstr.) 45 p.
141 Cassava Flour and Starch: Progress in Research and Development
Larsonneur, S. 1993. Influence du séchage Ruiz, R. 1988. Informe de actividad: solaire sur la qualité de l’amidon Programa de apoyo a las empresas aigre de manioc. Mémoire ingénieur. productoras de almidón de yuca en Université Tecnologique de Compiègne el norte del Cauca. Corporación and CIAT, Cali, Colombia. 114 p. para Estudios Interdisciplinarios y Asesorías Técnicas (CETEC) and Laurent, L. 1992. Qualité de l’amidon aigre de Servicio de Desarrollo y Consultoría manioc: Validation d’une méthode para el Sector Cooperativo y de d’évaluation du pouvoir de Micro-Empresas (SEDECOM), Cali, panification et mise en place d’une Colombia. épreuve descriptive d’analyse sensorielle. Mémoire ingénieur. ______. 1991. Agroindustria de Université Tecnologique de almidón agrio en el norte del Compiègne and CIAT, Cali, Colombia. Cauca. In: [Proceedings of the 88 p. workshop on] “Avances sobre Almidón de Yuca” held at CIAT, Nakamura, I. M. and Park, Y. K. 1975. Some Cali, Colombia, 17-20 June 1991. physico-chemical properties of (Abstr.) fermented cassava starch (polvilho azedo). Starch/Stärke 27(9):295-297. Vanhamel, S.; Van den Ende, L.; Darius, P. L.; and Delcour, J. A. 1991. A Pinto, R. 1978. Extracción de almidón de volumeter for breads prepared from yuca en rallanderías. ICA (Inst. 10 grams of flour. Cereal Chem. Colomb. Agropecu.) Informa 12(9):3-6. 68(2):170-172.
142 Physicochemical Properties of Cassava Sour Starch
CHAPTER 17
PHYSICOCHEMICAL PROPERTIES OF CASSAVA SOUR STARCH1
C. Mestres*, X. Rouau**, N. Zakhia***, and C. Brabet†
Introduction If pandebono is to expand, as in wheat bread, gas must form and be This chapter describes a collaborative retained. Retention supposes that study involving CIRAD, the Institut the dough has viscoelastic properties national de recherche agronomique that make it gas-tight. Viscoelastic (INRA), and CIAT. The study materials in food are generally investigated the physicochemical polymers and polymer networks. bases of baking pandebono, a They can be proteins such as gluten Colombian traditional bread, using in wheat bread, nonstarch cassava sour starch samples provided polysaccharides such as pentosans in by CIAT. We evaluated the rye bread, or exopolysaccharides from physicochemical modifications of sour microorganisms often added in (i.e., fermented) starch during nonwheat bread recipes (e.g., fermentation and drying and tried to dextran). Pentosans need oxidative relate them with the starch’s reticulation, and starch expansion property and potential for gelatinization, to improve their making pandebono. rheological properties. We investigated all these possibilities to Pandebono dough, a mixture of explain gas retention in cassava sour sour starch, water, and cheese, starch. expands during cooking. This implies that gas is produced, which expands, thus increasing the product’s volume Determining the Presence (Figure 1). If sweet (i.e., unfermented) of Polymers in starch is used, expansion does not Pandebono Dough occur, because either no gas is produced, or it escapes from the Dufour et al. (Chapter 16, this dough. volume) describe collecting two sets of samples: (1) at different stages of fermentation (0 to 33 days), followed * Département des cultures annuelles (CA), by sun-drying for 8 h, and (2) after CIRAD, Montpellier, France. complete fermentation (33 days) and ** Institut national de recherche agronomique at different stages of sun-drying (0 to (INRA), Montpellier, France. 8 h). The resulting loaf volumes are *** CIRAD/SAR, Montpellier, France. † CIRAD/SAR, stationed at the Cassava shown in Figure 2. Utilization Section, CIAT, Cali, Colombia. We first determined the nitrogen 1. No abstract was provided by the authors. content of the starch samples, which
143 Cassava Flour and Starch: Progress in Research and Development
In unfermented starch, gas bubbles escape
Starch
Water In sour starch, gas bubbles are retained Cheese
Mixing Shaping Cooking
Figure 1. Presumed mechanism of expansion in pandebono dough during cooking. Pandebono is a traditional cheesebread eaten in Colombia.
8 After 8 h of sun-drying was very low, ranging between 0.3 and 0.6 g/kg and implying about 6 0.2% as protein (Figure 3). Fermentation even decreased nitrogen 4 content slightly. Proteins are, therefore, highly unlikely to directly influence the viscoelastic properties of 2 sour starch. /g) 3 0 The samples’ pentosan content 010203040ranged from 6 to 7 g/kg and did not Duration of fermentation (days) change significantly with the duration of fermentation (Figure 4). These polysaccharides originated from 8 After 33 days of fermentation residual fibers of cassava roots, Loaf volume (cm rather than from production of 6 pentosan-like polymers by microorganisms during fermentation. 4 The molecules of phenolic compounds are efficient oxidative 2 reticulation agents of pentosans, improving their functional properties. 0 They can also absorb ultraviolet light, 02468which greatly increases their activity Sun-drying (hours) as oxidative agents. However, we found only traces of ferulic acid, Figure 2. Loaf volumes of pandebono (traditional which probably originated from Colombian cheesebread) obtained in two sets of samples. Data from residual fibers. We could not Dufour et al., Chapter 16, this determine whether sour starch volume. contains dextran because this
144 Physicochemical Properties of Cassava Sour Starch
0.6 molecule is very similar to starch and After 8 h of sun-drying cannot be separated from it.
0.5 Protein and pentosan contents of pandebono dough are too low to have a significant influence on the viscoelastic properties of sour starch 0.4 in general, and on gas retention in particular.
0.3 0 10203040 Duration of fermentation (days) The Role of Gelatinization in Gas Retention 0.6 Nitrogen (g/kg) After 33 days of fermentation Apart from cheese, starch remains the main component of pandebono 0.5 (95%-98% dry matter). We therefore studied the gelatinization and rheological properties of starch to determine whether fermentation and 0.4 drying modify it in a way that would explain sour starch’s ability to expand and retain gas. 0.3 02468 Sun-drying (hours) We determined starch’s thermal properties by using differential scanning calorimetry (DSC). We Figure 3. Nitrogen content (g/kg) of cassava sour starch samples. heated starch at a constant rate of 10 °C/min and measured the heat-flux between 35 to 140 °C. This way we could determine the gelatinization onset temperature (the intercept of base line and tangent to the energy change) and the enthalpy change (the area of heat flux during 8 the gelatinization transition) (Figure 5).
1234 1234 12341234 1234 1234
1234 1234 1234 12341234 1234 1234
6 1234 1234 1234 1234 12341234 1234 1234
1234 1234 123451234 12341234 12341234 12341234 123412345
12345 1234 12345 1234 1234 12345 1234 12345 12345 1234 12345 1234 1234 12345 1234 12345 Table 1 gives the results for the 12345 1234 12345 1234 1234 12345 1234 12345
12345 1234 12345 1234 1234 12345 1234 12345 12345 1234 12345 1234 1234 12345 1234 12345 most significant samples: unfermented 4 12345 12345 1234 1234 12345 12345 starch, oven-dried sour starch, and sun-dried sour starch. Only the last (% dry basis) 2 sample expanded well. The cassava Content of pentoses samples did not differ markedly in
0 their thermal properties: for all, 0 3 7 9 13192633 gelatinization temperature was close to 60 °C and enthalpy change to 16 J/g. Duration of fermentation (days) Fermentation and drying did not significantly modify the thermal Figure 4. Sugar content of cassava sour starch samples after total acid hydrolysis properties of starch crystallites, thus the specific expansion property of sour (glucose is not 123reported). ( = xylose; 12
123 12 = arabinose;123 = ribose; 12 starch cannot be explained by changes = rhamnose.) in crystallites.
145 Cassava Flour and Starch: Progress in Research and Development
Table 1. Thermal propertiesa of cassava starch samples.
Sample Fermentation Sun-drying In pH 4.0 In water In pH 7.0 of starch (days) (h) buffer buffer
GT EC GT EC GT EC GT EC GT EC
Maize 0 0 0 0 66.2 14.3 - - 69.0 14.7 Cassava 1b 0 0 8 8 60.5 16.6 59.8 16.7 63.9 17.4 Cassava 2c 33 33 8 8 60.6 15.5 60.2 16.1 63.5 17.3 Cassava 3d 33 33 0 0 60.5 16.1 60.3 16.3 64.0 16.7 a. GT = gelatinization temperature (° C); EC = enthalpy change (J/g dry basis). b. Unfermented cassava starch. c. Sour, oven-dried cassava starch. d. Sour, sun-dried cassava starch.
We then characterized the rheological properties of cassava 19 starches. We made viscoamylographic determinations 17 with the Rapid Visco Analyzer, a EC similar device to the Brabender viscoamylograph. We measured 15 pasting temperature, maximum Heat flux (mW) viscosity, and gelification index GT (Figure 6). 13 40 60 80 100 Our results (Figure 7) confirm Temperature (°C) those obtained at CIAT (Dufour et al., Figure 5. Enthalpy change (EC) and Chapter 16, this volume): gelatinization temperature (GT) of cassava starch observed with (1) The pasting temperature is similar differential scanning calorimetry. for all samples (which matches the DSC measurements).
200 Maximum viscosity 90 160 Gelification 120 70
80
Pasting temperature 50 Temperature (°C)
Viscosity (RVA units) 40
0 30 0 5 10 15 20 25 Time (minutes)
Figure 6. Viscosity profile of cassava sour starch observed by using a Rapid Visco Analyzer (RVA). ( = viscosity; ...... = temperature.)
146 Physicochemical Properties of Cassava Sour Starch
80 250 200
200 160 60
150 120 40 100 80 (RVA units) 20 50 40 Maximum viscosity
0 0 0 010203040 46 810 Duration of fermentation after pH 8 h of sun-drying (days) Figure 8. Influence of pH on the maximum 80 250 viscosity of cassava sour starch samples. (...... = unfermented, sun-dried; o = fermented 33 days,
Pasting temperature (°C) 200 60 artificially dried; -- -- = fermented
Maximum viscosity (RVA units) 33 days, sun-dried; RVA = Rapid Visco 150 Analyzer.) 40 100 20 Consequently, the maximum 50 viscosity is similar for all samples in 0 0 an acid medium. We hypothesized 0246810 that the sour starch with the best Sun-drying after 33 days expansion property may contain an of fermentation (hours) amylase that hydrolyzes the product during measurement, lowering the Figure 7. Variation of pasting temperature (- -) and maximum viscosity (- -) for two viscosity of the medium. Because this sets of samples of cassava sour starch amylase should be active in neutral in phosphate buffer at pH 7.0. and basic pH, we tried to determine (RVA = Rapid Visco Analyzer.) amylase activity within this sample by establishing the presence of reducing sugars and starch solubility. That is, (2) The maximum viscosity decreased if exo-amylase activity exists, with increased duration of reducing sugars should be released fermentation and sun-drying. with time, but if endo-amylase This figure seemed related to the activity exists, then starch solubility loaf volume of pandebono: the would increase with time. lower the maximum viscosity, the higher the loaf volume. In fact, we did not find change in either of these two parameters. This These observations were made indicates that amylase activity is with samples in a pH 7.0 buffer either very low or nonexistent. without amylase inhibitor. However, pH did have a significant effect We then investigated the (Figure 8): in fermented and sun-dried macromolecular structure of starch, sour starch, which had the best determining intrinsic viscosity by expansion property, maximum making the starch soluble with alkali viscosity continuously decreased as (pH 13). Intrinsic viscosity represents pH increased from 4 to 10. This the hydrodynamic volume of the phenomenon did not occur for molecules (polymers) and depends on starches unsuitable for pandebono two factors: first, the molecular making, such as unfermented starch weight of the polymer—the higher the or oven-dried sour starch. molecular weight, the higher the
147 Cassava Flour and Starch: Progress in Research and Development intrinsic viscosity—and, second, the (1) A decrease of molecular weight— conformation of the molecules—the unlikely, because of the lack of less “folded” they are in solution, the amylase activity. higher the intrinsic viscosity. (2) A change in macromolecular conformation and increased The intrinsic viscosity follows the convolution through interaction same pattern as the maximum with other molecules. Such viscosity observed on the amylograph interaction facilitates polymer (Figure 9): it decreases within the first folding. days of fermentation and within the first hours of sun-drying. 8
180 After 8 h of sun-drying 6 160 4 140
2 120 /g) 3
100 0 6 80 0 10203040
Duration of fermentation (days) Loaf volume (cm 4 200 After 33 days of fermentation
Intrinsic viscosity (ml/g) 170 2
140
0 110 100 120 140 160 180 200 Intrinsic viscosity (ml/g) 80 Figure 10. Relationship between intrinsic 50 viscosity of sour starch from two 0246810 cassava varieties and pandebono loaf Sun-drying (hours) volumes. ( = variety ‘Amarga’; = variety ‘CMC 40’; pandebono = a Figure 9. The intrinsic viscosity of two sets of traditional cheesebread eaten in samples of cassava sour starch. Colombia.)
A marked relationship therefore exists between intrinsic viscosity and Conclusions the pandebono’s loaf volume: the lower the viscosity, the higher the loaf We did not see any differences in the volume (Figure 10). We confirmed crystalline structure of starch, but we this relationship with another set of showed that viscosity of solubilized samples from a different cassava (intrinsic viscosity) or dispersed variety (CMC 40). How can the (viscoamylograph) starch decreases lowering of intrinsic viscosity be with increased fermentation and explained? sun-drying. Such reduction in
148 Physicochemical Properties of Cassava Sour Starch viscosity seems related to the have occurred with other molecules, pandebono’s loaf volume, but is either lactates or derivatives of lactic observed only at neutral and basic acid. Lactates cause starch to pH, and after 2 h of sun-drying but plasticize, and the effect is so notable not after 33 days of fermentation. It that a patent has recently been taken is not linked to an amylase or acidic out. Through lactates starch degradation of starch. derivatives can be obtained. Volatile derivatives of lactic acid may We can only propose some contribute to gas production, and to hypotheses to explain our results. the flavor and smell of sour starch. If The starch may have undergone an flammable, their flame colors could oxidative degradation (possible in indicate the quality of a sour starch. oven-drying). Or interactions may
149 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 18
INFLUENCE OF GELATINIZATION CHARACTERISTICS OF CASSAVA STARCH AND FLOUR ON THE TEXTURAL PROPERTIES OF SOME FOOD PRODUCTS
S. N. Moorthy*, J. Rickard**, and J. M. V. Blanshard***
Abstract lipids or sugars, probably makes the most important contribution to flour Cassava flour contains fiber, sugars, texture. The importance of these and smaller quantities of lipids and findings to the texture of food products other components. It exhibits made from cassava flour and starch is properties different from those of discussed. cassava starch, which cooks to a more cohesive paste. The gelatinization characteristics of starch and flour, Introduction extracted from selected cassava cultivars, were examined. The peak Cassava is an important root crop in viscosity of flour was generally lower many tropical countries, where the than that of starch, although more starchy and tuberous roots are eaten stable. Swelling volumes were also in various forms, including as starch correspondingly lower. The and flour. The starch is extracted by a gelatinization temperature of flour, wet process and the flour obtained by whether ascertained by differential milling dried chips. scanning calorimetry or viscography, was consistently several degrees The texture of cooked roots differs higher than that of starch. The widely between cultivars, and lower peak viscosity and higher considerable work has been carried out gelatinization temperature probably to identify reasons for this variability contribute significantly to the textural (Asaoka et al., 1992; Kawano et al., differences between flour and starch. 1987; Moorthy et al., 1993a; Defatting and ethanol extraction had Safo-Katanka and Owusu-Nipah, little influence on the gelatinization 1992; Wheatley et al., 1993). Few characteristics of either starch or conclusions have been reached but the flour, indicating that fiber, rather than quantity and quality of the starch in the root and the presence of various nonstarchy polysaccharides are considered important.
* Division of Postharvest Technology, Central Several differences also exist in Tuber Crops Research Institute (CTCRI), the rheological and functional Trivandrum, India. properties between starch and flour. ** Natural Resources Institute (NRI), Chatham, UK. We attempted to identify the reasons *** University of Nottingham, UK. for these differences.
150 ...Gelatinization Characteristics of Cassava Starch and Flour...
Materials and Methods Lipids, in common with many surfactants, significantly affect starch Starch and flour were obtained from by complexing strongly with amylose five cultivars of freshly harvested and amylopectin side chains, cassava roots (M-4, H-165, H-1687, rendering these less labile (Krog, S-856, and H-97), each having 1973). This capacity has been different cooking qualities. The main exploited for reducing the constituents of the samples—starch, cohesiveness of potato starch products fiber, lipids, and sugars—were (Hoover and Hadziyev, 1981, 1982). determined by standard procedures. Low levels of surfactants can have a To assess the influence of lipids, profound effect on cassava starch samples were defatted by extraction (Moorthy, 1985). Ethanol-soluble (Soxhlet), using petroleum ether constituents in the flours ranged from (40-60 °C). Ethanol extraction was 2.5% to 3.7% and only 0.9% to 1.3% similarly undertaken, with 80% in the starch samples (data not ethanol (Soxhlet, 6 h), to examine shown). The predominant sugar in the influence of sugars and cassava flour has been identified as ethanol-soluble components. sucrose.
Differential scanning calorimetry The recorded gelatinization (DSC) data were obtained by using temperatures (Table 2) reveal a Perkin Elmer DSC-2 equipment with consistent difference between the flour Indium as a standard (temperature and starch samples. Comparing range 25-100 °C, at a heating rate of values for initial, maximum, and end 10 °C/min). Gelatinization profiles of temperatures, the results for flour the samples (5%) were obtained on a are each 2-3 °C higher than for the Brabender Viscoamylograph (350 cmg corresponding starches. Components [torque] sensitivity cartridge, heating within the flour, by restricting access rate 1.5 °C/min). Swelling volumes of water into the starch granules, can were determined at 95 °C (Schoch, delay gelatinization. Surfactants 1964). and lipids, by forming complexes, are known to raise gelatinization temperatures (Osman, 1967). Results and Discussion However, the defatted and ethanol-extracted flours had the same Table 1 presents the results of the values as native flour, indicating that chemical analyses of starch and flour neither lipids nor sugars were from the five cassava varieties. responsible for enhanced Starch content on a dry weight basis gelatinization temperatures. Recent was 98% or more in all the starch experiments on cassava starch show samples and between 79.1% and correlation between higher fiber 86.0% in the flour samples. Crude content and higher gelatinization fiber content was 0.13% or less in the temperatures (Moorthy et al., 1993a). starch samples, whereas it ranged Thus, the elevation in gelatinization from 1.50% to 2.98% in the flour. temperature of flour may be attributed Earlier studies show similar starch to the fiber. and fiber compositions (Abraham et al., 1979). The DSC peak patterns of starch and flour from the same cultivar were The lipid content, by nature much similar. ‘H-97’ starch and flour had a lower than that of cereals, varied from characteristic shoulder in their peaks, 0.11% to 0.22% in the starches and whereas ‘M-4’ starch and flour had from 0.25% to 0.56% in the flours. typically broad peaks. The peak
151 Cassava Flour and Starch: Progress in Research and Development
Table 1. Biochemical constituents of starch and flour made from five cassava varieties.
Variety Product Starch Sugar Lipids Crude fiber (%) (%) (%) (%)
M-4 Starch 98.1 - 0.11 0.11 Flour 86.0 2.20 0.45 1.50
H-165 Starch 98.0 - 0.22 0.13 Flour 79.1 3.49 0.27 2.98
H-1687 Starch 98.2 - 0.18 0.15 Flour 80.5 2.72 0.29 2.23
S-856 Starch 98.5 - 0.20 0.12 Flour 81.2 3.23 0.56 2.56
H-97 Starch 98.3 - 0.20 0.11 Flour 82.7 3.05 0.25 2.70
Table 2. Data from differential scanning calorimetry (DSC) of cassava starch and flour.
Variety Product Temperature (°C) ∆Ha (cal/g) Initial Maximum End
M-4 Starch 68.10 73.24 78.54 2.95 Flour 71.11 75.67 81.29 2.02
H-165 Starch 65.35 69.22 74.86 3.27 Flour 68.65 72.02 77.19 2.14
H-1687 Starch 67.12 71.45 75.39 2.15 Flour 70.02 73.90 79.11 2.22
S-856 Starch 65.62 70.14 74.94 2.65 Flour 68.72 72.92 76.95 2.09
H-97 Starch 69.36 72.29 77.13 3.43 Flour 71.82 75.02 79.92 2.27 a. ∆H = Enthalpy change.
patterns were not modified by gelatinization temperatures in the defatting or by ethanol extraction, DSC results for the flour samples indicating dependence on the starch are supported by the Brabender granular structure. The enthalpy of viscographic data (Table 3), which gelatinization of flour was lower than show that pasting temperatures for that for starch for every variety and flours were 3-5 °C higher than for the neither defatting nor ethanol respective starches. extraction affected the values to any noticeable extent. However, the lower The peak viscosity and viscosity enthalpy for the flour can be breakdown for each flour were attributed in part to the lower starch different from those of the content of the samples. The enhanced corresponding starch, and most
152 ...Gelatinization Characteristics of Cassava Starch and Flour...
Table 3. Viscosity and swelling properties of cassava starch and flour.
Variety Producta Viscosity (BU)b Break-down Pasting Swelling temp. (°C) vol. (ml/g) V97 VH
M-4 Starch 540 380 160 68-73 32.0 Flour 380 320 60 71-74 28.0 Starch (d.) 580 440 140 70-76 33.5 Flour (d.) 380 310 70 72-75 29.5 Starch (e.) 560 420 140 70-75 33.0 Flour (e.) 410 380 30 72-76 29.0
H-165 Starch 940 480 460 66-78 38.5 Flour 460 380 80 71-75 32.0 Starch (d.) 1,000 580 420 69-82 39.5 Flour (d.) 440 360 80 72-76 33.5 Starch (e.) 1,000 520 480 69-83 39.5 Flour (e.) 470 380 90 71-78 33.0
H-1687 Starch 540 480 60 70-81 33.5 Flour 460 440 20 71-83 29.5 Starch (d.) 570 510 60 71-82 33.5 Flour (d.) 440 390 50 70-80 29.0 Starch (e.) 520 480 40 70-83 34.0 Flour (e.) 440 400 40 71-83 29.5
S-856 Starch 500 340 160 67-80 33.0 Flour 440 360 80 71-86 29.0 Starch (d.) 580 390 190 69-75 33.5 Flour (d.) 470 380 90 70-85 29.5 Starch (e.) 490 360 130 69-75 34.0 Flour (e.) 740 390 80 70-89 30.0 a. (d.) = after defatting; (e.) = after ethanol extraction. b. V97 = viscosity at 97 °C; VH = viscosity after holding at 97 °C.
pronounced in the comparatively affecting starch granule expansion and much lower peak viscosity of flour from breakdown. ‘H-165’. Again, the lower starch content in the flour samples can Defatting and ethanol extraction account in part for the low readings. slightly enhanced paste viscosity in However, while the viscosity was lower, starch, whereas flour samples remained it was more consistent throughout the unaffected. In contrast, the slight temperature program. Stabilization increase in the flours’ pasting occurs through the presence of temperature was probably due to the nonstarchy components in the flour. continuing presence of fiber in the Lipids, although known to stabilize defatted ethanol-extracted samples. starch viscosity (Krog, 1973), had little Similar results have been obtained in a effect here. The absence of fiber-rich starchy flour extracted from stabilization in the ethanol-extracted fermented roots (Moorthy et al., 1993b). samples indicates that sugars were not According to Osman (1967), high levels involved either. The reduced viscosity of sugars are needed to bring about noted in all varieties was most perceptible changes in the viscosity of pronounced in ‘H-165’, which had the starch. The absence of significant highest crude fiber content. Stability changes in the peak viscosity of flours may therefore result from the fiber and starches thus indicates that sugars
153 Cassava Flour and Starch: Progress in Research and Development do not greatly influence viscosity in and hemicellulose) and their interaction cassava. with starch. It should also focus on how rheological characteristics can lead to Neither defatting nor ethanol different functional properties in starch extraction affected swelling volumes of and flour. the starches and flours, further indicating the influence of fiber in modifying starch rheological properties Acknowledgments in the flour. We thank the Director of the CTCRI Cassava starch, cooked in water, and Dr. C. Balagopalan, Head of the generally gives a cohesive, long paste, PHT Division, CTCRI, for their kind whereas flour texture is less cohesive. help and encouragement. Cohesiveness is attributed to the breakdown of starch molecules during heating and stirring. Early References gelatinization can render starch more susceptible to breakdown because it Abraham, T. E.; Raja, K. C. M.; Sreedharan, undergoes a longer period of shear. V. P.; and Sreemulanathan, H. 1979. High swelling necessitates the Some quality aspects of a few varieties of cassava. J. Food Sci. Tech. 16:237-239. weakening of associative forces and thus easier breakdown of starch. The Asaoka, M.; Blanshard, J. M. V.; and Rickard, fiber may act as a barrier to earlier J. E. 1992. Effects of cultivars and gelatinization and to higher swelling, growth on the gelatinization properties of cassava (Manihot esculenta Crantz) reducing the cohesiveness of the paste. starch. J. Sci. Food Agric. 59:53-58.
Starch can act, for example, as a Hoover, R. and Hadziyev, D. 1981. The effect of monoglycerides on amylose binder, thickener, or glazing agent in complexing during a potato granule different foods (Smith, 1982[?]). In process. Starch/Stärke 33:346-355. products where a cohesive texture is ______and ______. 1982. Effect of desired, such as gravies and puddings, monoglyceride on some rehydration starch would be favored, whereas in properties of potato granules. products where a nonsticky consistency Starch/Stärke 34:152-158. is sought, flour would be more suitable. Kawano, K.; Fukuda, W. M. G.; and Cenpukdee, These mirror the findings of U. 1987. Genetic and environmental comparative studies conducted at the effects on dry matter content of cassava Central Tuber Crops Research Institute root. Crop. Sci. 27:69-74. (CTCRI) for starch and flour in locally Krog, N. 1973. Amylose complexing effect of produced extruded products (when food-grade emulsifiers. Starch/Stärke starch was used, the product tended to 23:206-210. be hard and oily; with flour, the same product was crisp and nonsticky). Moorthy, S. N. 1985. Effect of different types of surfactants on cassava starch Similarly, food items prepared from properties. J. Agric. Food Chem. starchy flour made from fermented 33:1227-1232. roots had a higher fiber content and better texture. ______; Blanshard, J. M. V.; and Rickard, J. E. 1993a. Starch properties in relation to cooking quality of cassava. In: Roca, The study thus clearly indicates W. M. and Thro, A. M. (eds.). Proceedings that fiber is a significant determinant of the First International Scientific of the characteristics and functional Meeting, Cassava Biotechnology properties of cassava starches and Network, Cartagena de Indias, Colombia, 25-28 August 1992. Working document flours. Future work should examine no. 123. CIAT, Cali, Colombia. specific fiber components (e.g., cellulose p. 265-269.
154 ...Gelatinization Characteristics of Cassava Starch and Flour...
______; George, M.; and Padmaja, G. Schoch, T. J. 1964. Swelling power and 1993b. Functional properties of solubility of granular starches. In: the starchy flour extracted from Whistler, R. L. (ed.). Methods in cassava on fermentation with a carbohydrate chemistry, vol. 4. Academic mixed-culture inoculum. J. Sci. Press, New York, NY, USA. p. 106-108. Food Agric. 61:442-447. Smith, P. S. 1982[?]. Starchy derivatives and Osman, E. M. 1967. Starch in the food their use in foods. In: Linebeck, D. R. industry. In: Whistler, R. L. and and Inglett, G. E. (eds.). Food Paschall, E. F. (eds.). Starch carbohydrates. AVI Publications, chemistry and technology, vol. 2. Westport, CT, USA. p. 237-258. Academic Press, New York, NY, USA. p. 163-215. Wheatley, C. C.; Orrego, J. I.; Sánchez, T.; and Granados, E. 1993. Quality evaluation Safo-Katanka, O. and Owusu-Nipah, J. of the cassava core collection at CIAT. 1992. Cassava varietal screening In: Roca, W. M. and Thro, A. M. (eds.). for cooking quality: relationship Proceedings of the First International between dry matter, starch Scientific Meeting, Cassava content, mealiness and certain Biotechnology Network, Cartagena de microscopic observations of the Indias, Colombia, 25-28 August 1992. raw and cooked tuber. J. Sci. Food Working document no. 123. CIAT, Cali, Agric. 60:99-104. Colombia. p. 255-264.
155 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 19
TWO RAPID ASSAYS FOR CYANOGENS IN CASSAVA: THEIR EVALUATION, MODIFICATION, AND COMPARISON
G. M. O’Brien* and C. C. Wheatley**
Abstract in 68% of cases compared with 66% by the T.B. assay. The T.B. assay, Two rapid, semiquantitative assays however, performed more reliably with for total cyanogens in cassava were low cyanogen samples, whereas the evaluated. These were the rapid picrate assay was more reliable with picrate paper test, now well-known, intermediate cyanogen samples. The and a recently proposed, rapid, paper sampling protocol used at CIAT for test that involves the reagent tetra the rapid assay of cyanogen contents base (T.B.; 4,4'-methylenebis- of cassava clones was also evaluated. [N,N-dimethylaniline]). A precise colorimetric assay was used as control. After preliminary evaluation, Introduction both assay methods underwent modification to improve accuracy of Cassava (Manihot esculenta Crantz) is scoring. As a result, the reliability of the fourth most important food crop the picrate assay was greatly of the tropics (Cock, 1985). An improved. The T.B. assay was efficient source of low-cost modified in the interests of safety. carbohydrates, cassava is important Evaluation of the latter assay over a for food security, particularly in range of temperatures from 20 to Africa, and as an industrial raw 35 °C showed no significant effects of material, especially in Asia and Latin temperature on performance when America. Cyanogens have long been the new scoring system was used. recognized as a toxic component of The level of endogenous linamarase cassava’s edible roots and leaves. activity in each sample was an The cyanogenic contents of the roots influential factor in rapid assay can vary from less than 10 to more performance. In a series of than 500 mg/kg, measured as comparative trials in three distinct hydrogen cyanide (HCN), on a fresh ecosystems, the newly modified weight basis (fwb). picrate assay produced correct results Guignard first developed the alkaline picrate assay for cyanide in 1906. It was introduced in a semiquantitative, rapid format to * Natural Resources Institute (NRI)/CIAT, CIAT and the International Institute currently Research Fellow at CIAT. of Tropical Agriculture (IITA), Nigeria, ** Centro Internacional de la Papa (CIP), during the 1970s as a routine assay stationed at Bogor, Indonesia. in cassava breeding programs. The
156 Two Rapid Assays for Cyanogens in Cassava:... rapid picrate assay is based on have carried out controlled producing a red-brown color whose evaluation and comparison of the intensity increases with the quantity two assay methods in three distinct of HCN liberated from the sample. tropical environments in Colombia The HCN is liberated by autolysis under field conditions. and results from the hydrolytic action of the endogenous enzyme, linamarase, on cyanogenic Reagents glucosides in the sample. The picrate system, when used Picric acid (99%), copper (II) acetate quantitatively, has been observed to (99%), toluene (99.5%), sodium produce very high results from carbonate (99.5%, anhydrous) cassava compared with other (E. Merck, Darmstadt, Germany), quantitative methods and T.B. (Sigma Chemical Company, (Izomkun-Etiobhio and Ugochukwu, St. Louis, USA) were used for the 1984; Mendoza et al., 1984). The rapid methods. Reagents used for assay has been criticized for falsely the colorimetric quantitative detecting cyanogens in acyanogenic cyanogen assay were as described samples (Nahrstedt, 1980). The by O’Brien et al. (1991). rapid picrate assay originally used with a 9-point scale at CIAT has Alkaline picrate mixture was been criticized for giving poor composed of picric acid (5 g) and correlation between cyanogen sodium carbonate (25 g, anhydrous) content and result (CIAT, 1993). dissolved in water and made up to 1 liter. More recently, an alternative, rapid semiquantitative assay was The T.B. mixture was as developed, based on the reagent described by Bradbury and Egan tetra base (T.B.; [4,4'-methylenebis- (1992), a 1:1 (v/v) mixture produced [N,N-dimethylaniline]). Also known on a daily basis, using two reagents: as Michler’s reagent, T.B. was originally used for qualitative assay (1) Copper (II) acetate, 3 g/L in 15% of cyanogens (Feigl and Anger, acetic acid. 1966). The modified T.B. method (2) Tetra base, 3 g/L in acetone. was proposed as more sensitive and rapid than picrate (Bradbury and According to Bradbury and Egan Egan, 1992). In this test, a (1992), the two reagent solutions blue-violet color forms, which should be stable for several months. increases in intensity and in violet But we noted a slight darkening of hue the higher the sample’s the reagent mixture made from cyanogen content. reagents 3 weeks old and older. Reagents were therefore freshly We have evaluated both the made every 3 weeks. picrate and the T.B. rapid methods, using a reliable quantitative Because of the highly toxic and colorimetric assay (Cooke, 1978; carcinogenic nature of T.B., nitrile O’Brien et al., 1991) as control. The rubber gloves were used in handling. assay method(s) selected after this The T.B. reagent was prepared and evaluation would be expected to stored in a fume-cupboard. perform well in any cassava-growing environment. Because ambient Reagents for assay of linamarase temperatures in the tropics and activity were as described by Cooke subtropics vary considerably, we (1979).
157 Cassava Flour and Starch: Progress in Research and Development
The Tetra Base Assay buildup of HCN in the vial. The assay was then carried out. The T.B. rapid assay of Bradbury and Egan (1992) represented a new To start the assay, the stopper in development in cassava cyanogen the sample vial was replaced by a assay, which had been tested, using similar stopper with a T.B. test-paper only low-cyanogen cultivars. The attached, so that the paper was assay was also reported to be a suspended inside the vial, 1 cm above little more rapid at higher ambient the sample. The blue-violet color temperatures, suggesting that produced at the bottom end of the changes in temperature may affect paper was recorded after 10 and the endogenous linamarase in a 60 min. The result was interpreted in given sample (J. H. Bradbury, 1992, terms of cyanogen content. personal communication). The T.B. test-paper was made as This reference to linamarase follows: paper strips (Whatman’s enzyme also prompted interest in no. 1 filter paper, 4 x 1 cm) were the relationship between the attached to clean vial stoppers with amount of endogenous linamarase adhesive tape. A 1-cm portion at one in a given sample, its activity under end of the paper was attached to the given environmental conditions, stopper, leaving a length of 3 cm to and, consequently, the reliability of act as support for the T.B. mixture. autolytic assays. Thus, evaluating The stoppers and papers were placed the T.B. assay in some detail within the fume cupboard. One drop became necessary. At CIAT, of T.B. mixture was placed on each Palmira, the T.B. assay was run at paper at the end away from the different temperatures, with an stopper. The drops of mixture were assay of endogenous linamarase left to soak through before each paper activity in parenchyma surrounding was sealed in an empty vial for safety, the sample taken for the T.B. assay. before assay. The quantitative, colorimetric assay of cyanogen content was used as To evaluate the T.B. assay control. The duration of the assay method, assays were made of 72 was determined after constantly cassava roots from 10 varieties, observing samples under assay for ranging between 10 and 456 mg/kg 3 h and after an overnight period. total cyanogens (as HCN, fwb). In The testing of the method resulted each case, the root was first sampled in a 1-h assay. for T.B. assay, then the rest of the peeled root was assayed for both total Conducting the assay cyanogens and endogenous linamarase activity (Figure 1) by The T.B. assay was carried out in quantitative colorimetric assay quadruplicate. A central disc was (Cooke, 1978; O’Brien et al., 1991). sliced out crosswise from a cassava root and parenchymal plugs Tetra base assays were carried removed (Figure 1). The plugs were out at 20, 25, 30, and 35 °C, using an trimmed with a scalpel to 0.5 cm incubator. At least one root from thick, placed individually in small each of the 10 cassava clones used in glass vials (2 x 5 cm), and sealed the experiment was assayed at each with tightly fitting, plastic stoppers. temperature. The samples were The plugs were maintained in the stored in the incubator during the 1-h vials for 1 h before assay, to allow preassay period and during the assay
158 Two Rapid Assays for Cyanogens in Cassava:...
A
B
Figure 1. Steps in sampling a cassava root for rapid and quantitative cyanogen assays. (A) The root is first measured longitudinally and a disc, 1 cm thick, is removed from the center. (B; i) The geometric radius of the disc is measured from the center to the inner edge of the peel. (ii) Half way along a radius, a 1-cm round plug is removed with a borer. The plug is used for the tetra base assay. The sampling is replicated four times. (iii) From the space between two plugs, again half way along a radius, a 1-cm cube is cut out with a scalpel. The cube is used for the picrate assay. (iv) The rest of the root is peeled and the parenchyma chopped into cubes of about 1 cm3. From these, a random sample of 50 g is quantitatively assayed for total cyanogens. Where required, another 50-g sample is taken for a linamarase enzyme assay.
itself. A 10-point numerical scale was 8.5 and 10 within 10 min. devised, using the “Munsell color Accordingly, a system of scoring guide.” It was based on the intensity (Table 1) for total cyanogens in of color attained, differing from that cassava parenchyma was devised. used by Bradbury and Egan (1992). The maximum permitted error in this The scale ran from very pale blue to grouping method was ± 1 mg/kg. A deep violet. sample with a cyanogen content of 50.9 mg/kg could therefore be classed Figure 2 shows the scores either in range 1 or range 2. obtained by 72 roots in a 1-h test of their cyanogen contents. The relationship between total cyanogens Table 1. Tetra base rapid assay, grouping and T.B. score in the 1-h test was format. linear only to about 50 mg/kg (as Range Score Total cyanogens HCN, fwb). Most samples with (mg/kg as HCN, fwb) cyanogen contents greater than 50 mg/kg produced a score between 1 <8.5 0-50 8.5 and 10. Roots containing more 2 <8.5 after 10 min, than 100 mg/kg, almost without >8.5 after 1 h 50-100 exception, gave scores between 3 >8.5 after 10 min >100
159 Cassava Flour and Starch: Progress in Research and Development
12
10
8
6
4 Tetra base score
2
0 0 50 100 150 200 250 300 350 400 450 500
Total cyanogens (as HCN, mg/kg, fwb)
Figure 2. Evaluation of the tetra base assay used at CIAT, Palmira, to determine the cyanogen content of 72 roots from 10 cassava varieties.
Of the 72 assays carried out in sample is neither grated nor this experiment, 61 results proved to macerated in buffer and where a be correct within the grouping significant degree of autolytic format shown in Table 1. Thus, breakdown of cyanogens is sought 84.7% of all results were correctly within 1 h. Cooke and De la Cruz assayed. (1982) found that 24 h in excess buffer was needed for a complete Influence of endogenous autolytic breakdown of cyanogens in linamarase activity a cassava sample. Yet, 84.7% of all results in this experiment were During the T.B. experimental work correctly assayed, regardless of at CIAT, the endogenous linamarase endogenous linamarase activity and activity of roots being assayed was of temperature within the range measured colorimetrically. Activity stated (20 to 35 °C). ranged between 0.03 and 0.63 enzyme units per gram (EU/g, fwb). This experiment and its results The T.B. score and colorimetric are described in greater detail assay correlated better when data elsewhere (O’Brien et al., 1993). points from samples with less than 0.2 EU/g were removed, reducing the total from 72 to 43 cases. The Picrate Assay Spearman correlation of linearity increased from 0.77 to 0.85. Hence, Plant breeding programs have been T.B. performance in roots with routinely using the alkaline picrate linamarase activity below 0.2 EU/g rapid assay for about 20 years, was negatively affected. unlike the relatively untested T.B. assay. The original scoring format, It is unsurprising that a used for the picrate assay, assigned sample’s endogenous linamarase a cyanogen-content range to each activity should affect results in a of the nine points on the system where the parenchymal color scale:
160 Two Rapid Assays for Cyanogens in Cassava:...
Score Total cyanogens toluene were placed on to the sample. (mg/kg, as HCN, fwb) The tube was tightly sealed with a 1 = pale yellow <10 rubber stopper, entrapping a strip of 210-15paper (Whatman’s no. 1, 6 x 1 cm), 315-25saturated in alkaline picrate mixture 425-40and suspended above the sample. 540-60After 10 h (Pivijay) or 12 h (Palmira 660-85 and Cajibío), the resultant color 7 85 - 115 8 115 - 150 change was noted and interpreted in 9 = dark brown >150 terms of cyanogen content.
Some time before this project began, CIAT had made a limited Field-Based Comparison of evaluation of the picrate rapid assay. the Two Rapid Methods, The original scoring format, with its with Colorimetric Control 9-point scale, was regarded as unworkable because of errors (CIAT, Three sites were selected for this 1993). The method of scoring was work: thus modified into anecdotal ranges: (1) Cajibío (near Popayán, Score Cyanogen contents southwestern Colombia): a 1-4 Low highland area, 2,000 m above sea 5-7 Medium level, temperatures were 19 to 8-9 High 26 °C during trials. (2) CIAT (Palmira, southwestern With the picrate assay, we Colombia): mid-altitude, 1,000 m evaluated only this “anecdotal” above sea level, temperatures were scoring system, assigning specific 26 to 33 °C during trials. quantities to the anecdotal ranges (3) Pivijay (North Coast, Colombia): at listed above. The assay was sea level, temperatures of 30 to compared with the evaluated and 34 °C during trials. modified T.B. assay, under field conditions, using the quantitative In this experiment, 100 roots colorimetric cyanogen assay as a from 12 different clones were assayed. control. Each root was sampled for both the rapid T.B. assay and the rapid For the picrate assay, a cube was picrate assay (Figure 1). The rest cut from the parenchymal disc taken of the root parenchyma then from the root (Figure 1) and placed underwent quantitative colorimetric in a 12-cm test tube. Five drops of assay.
Table 2. Scoring ranges and levels of accuracy for tetra base and picrate rapid assays.
Group Scoring ranges Assay accuracy (%)
1 2 3 TB Picrate Q. color.
A 0-50 50-100 100+ 66 68 100
B 0-40 40-90 90+ 61 73 100
C 0-60 60-110 110+ 68 65 100
161 Cassava Flour and Starch: Progress in Research and Development
Using the results of the 100 A analyses carried out, three range 123 123 groups of total cyanogen content (measured in mg/kg of HCN, fwb) 11 1 19 3 4 were considered for scoring in each 27 8 13 223 rapid assay and their levels of accuracy evaluated (Table 2). Group 3103217 B gave 73% correct results for picrate but only 61% for T.B. Group C gave B 65% for picrate and 68% for T.B. Group A gave the most favorable 123 123 proportion of correct results for both 1 11 1 the T.B. (66%) and picrate (68%) methods. 21 123 297
Of the three groups, group A was 3143210 adopted. Hence, the picrate rapid assay gave slightly but not C significantly better results than the 123 123 T.B. rapid assay. Also, the picrate scoring format was slightly modified: 1 12 7 the score 7 was reassigned to high 22 132 273 instead of intermediate cyanogen content. The scores were therefore 3310329 grouped as shown in Table 3. Figure 3 shows the results of Picrate assay score Tetra base assay score comparing the two assays.
Figure 3. Performance of picrate and tetra base Table 3. Picrate rapid assay, revised group assays in measuring total cyanogens format. in cassava grown in three ecosystems: A = CIAT, Palmira, mid-altitudes, Range Score Total cyanogens southwestern Colombia; B = Cajibío, (mg/kg as HCN, fwb) highlands, southwestern Colombia; C = Pivijay, sea level, North Coast, 1 1-4 0-50 Colombia. Values indicated on the 2 5-6 50 -100 graphs’ axes correspond to cyanogen content ranges (mg/kg, as HCN, fwb): 3 7-9 >100 1 = 0-50; 2 = 50-100; 3 = > 100. Correct results are reported in shaded boxes. Maximum error permitted is ± 1 mg/kg. Sensitivity to cyanogen content
A statistical study was carried out on the data from this experiment, using intermediate (range 2) and even some a box plot model (SAS statistical high (range 3) cyanogen samples. The analysis package). It was found that picrate assay wrongly classified a the methods produced different number of high and some low cyanogen interquartile ranges (IQR, samples as “intermediate.” For representing the central 50% of samples classified as “high” the IQRs results) for cyanogen content. were almost identical. Despite a small Range 1 denoted low cyanogen number of intermediate results content and range 2 intermediate. wrongly classified as “high,” nearly all The T.B. assay wrongly classified as samples with cyanogen contents of “low” (range 1) a number of 100+ mg/kg or more were correctly
162 Two Rapid Assays for Cyanogens in Cassava:... placed within range 3 in both particularly good for rapid screening. methods. But variations in sample linamarase activity constitute an inbuilt source of The findings of the three trials error for any rapid autolytic assay of suggest that the picrate assay cyanogens in cassava. Nonautolytic performs more reliably than the T.B. methods (for example, destruction of with roots containing 50-100 mg/kg the endogenous linamarase of the as HCN, whereas the T.B. assay is sample, followed by adding an excess more reliable than picrate with roots quantity of exogenous linamarase) are containing less than 50 mg/kg. more effective in this respect, but they are much slower for mass-screening Comparing the two assays across samples. Autolysis is therefore still ecosystems the only practicable system.
Figure 3 shows that the picrate assay performed less well than the T.B. at Evaluation of Field Sampling CIAT, Palmira (almost 48% correct, Method compared with 70%, respectively, Figure 3A). But, at Cajibío, the In the comparison trials undertaken picrate was better than the T.B. assay at Cajibío and Pivijay, the two rapid (87% compared with 67%, assays were compared, using the respectively, Figure 3B). At Pivijay, same root samples. The CIAT plant results were 77% for picrate breeders’ sampling method itself was compared with 60% for T.B. also tested for its representativeness, (Figure 3C). using the quantitative colorimetric assay. CIAT usually samples clones This apparent irregularity for mass screening from a plot of probably had more to do with 25 plants (5 x 5), selecting one plant samples’ cyanogen content than with near the center. From this plant, one other factors (temperatures were root is selected for rapid assay of total similar at CIAT and Pivijay). At CIAT, cyanogens. The result obtained from of the eight clones used, two this root is treated as representative produced roots whose cyanogen of the entire plot. contents belonged to range 1. These roots were all erroneously classified At Cajibío, plots containing under range 2 in the picrate assay, 25 plants of each clone, 13 months whereas the T.B. assay correctly old, were used. At Pivijay, rows of six classified them under range 1. In the plants per clone, 8.5 months old, other two trials, no low-cyanogen were used. In each case, one plant clone was used and the erroneous was harvested as representing its plot picrate results therefore did not recur. or row. From this plant, one root was chosen to represent the whole plant Interpreting the results of the (and therefore the whole plot or row). respective assays by means of the At the same time, a further four roots system chosen, no significant were taken from the same plant: their difference in overall performance was parenchyma was pooled and triplicate found between the two methods, with extracts made. Their assay served as overall success rates of 68% (picrate) control to show whether the chosen and 66% (T.B.). root represented the whole plant.
That both methods produced A further four plants were results of which more than 30% were harvested from the same plot or row. erroneous suggests that neither is The parenchyma of their roots was
163 Cassava Flour and Starch: Progress in Research and Development thoroughly chopped and pooled. of cassava cyanogens in all cases, Triplicate assays were taken to show except: if the chosen plant properly represented the entire plot or row, (a) where a significantly high and further, if the chosen root from proportion of low-cyanogen that plant properly represented the clones (0-50 mg/kg, fwb) are entire plot or row. used (i.e., where the risk of rejecting low-cyanogen The semiquantitative, rapid material would be high); and assays operate with three ranges of (b) where a very rapid result is cyanogen content. To be required. representative, the sample root taken from a given plot or row had to give a (2) Under circumstances described in result within the same range as the (1a) and (1b), the tetra base assay mean of the rest of the plot or row. should be used but only if: Analysis of the data from the trial for representativeness shows that, in 47 (a) a well-maintained fume cases out of 60 (i.e., in 78% of cases), cupboard and good disposal the selected root was found to be facilities are available; and representative both of the plant from (b) workers have been trained which it was taken and of the group and are willing to apply of five plants taken to represent the strict safety procedures. entire plot or row. Thus, the sampling method appears satisfactory, although it would be References desirable to continue and expand this investigation, extending it to other Bradbury, J. H. and Egan, S. V. 1992. Rapid cassava clones. screening assay of cyanide content of cassava. Phytochem. Anal. 3:91-94.
CIAT, Cassava Program. 1993. Activities Conclusions during 1989: utilization. In: Cassava Program report, 1987-1989. In comparing the Bradbury and Egan Working document no. 91. Cali, (1992) picrate assay with a newly Colombia. p. 567-568. modified T.B. assay, the success rates Cock, J. 1985. Cassava: new potential for a of both were very similar—68% for neglected crop. Westview Press, picrate and 66% for T.B. Boulder, CO, USA. 191 p.
The high toxicity and carcinogenic Cooke, R. D. 1978. An enzymatic assay for the total cyanide content of cassava nature of the reagent tetra base (Manihot esculenta Crantz). J. Sci. requires a comprehensive and Food Agric. 29:345-352. carefully controlled methodology. In terms of reagent costs, the T.B. assay ______. 1979. Enzymatic assay for is potentially less expensive than the determining the cyanide content of cassava and cassava products. CIAT, picrate assay, although costs Cali, Colombia. 14 p. associated with safety precautions and equipment are considerably ______and De la Cruz, E. M. 1982. An higher. In view of these findings, the evaluation of enzymic and following recommendations are made: autolytic assays for cyanide in cassava (Manihot esculenta Crantz). J. Sci. Food Agric. 33:1001-1009. (1) The newly modified, picrate assay should be used for rapid screening
164 Two Rapid Assays for Cyanogens in Cassava:...
Feigl, F. and Anger, V. 1966. Replacement of Munsell color guide. Kollmorgen Instrument benzidine by copper Corporation, Baltimore, MD, USA. ethylacetoacetate and tetra base as spot-test reagent for hydrogen Nahrstedt, A. 1980. Absence of cyanogenesis cyanide and cyanogen. Analyst from Droseraceae. Phytochemistry 91:282-284. 19:2757-2758.
Izomkun-Etiobhio, B. O. and Ugochukwu, O’Brien, G. M.; Taylor, A. J.; and Poulter, E. N. 1984. Comparison of an N. H. 1991. Improved enzymic assay alkaline picrate and a for cyanogens in fresh and processed pyridine-pyrazolone method for the cassava. J. Sci. Food Agric. determination of hydrogen cyanide in 56:277-289. cassava and in its products. J. Sci. Food Agric. 35:1-4. ______; Wheatley, C. C.; and Poulter, N. H. 1993. Evaluation of a rapid Mendoza, E. M. T.; Kojima, M.; Iwatsuki, N.; semi-quantitative assay for Fukuba, H.; and Uritani, I. 1984. cyanogensis in cassava. In: Roca, Evaluation of some methods for the W. M. and Thro, A. M. (eds.). analysis of cyanide in cassava. In: Proceedings of the First International Uritani, I. and Reyes, E. D. (eds.). Scientific Meeting, Cassava Tropical root crops: postharvest Biotechnology Network, Cartagena de physiology and processing. Japanese Indias, Colombia, 25-28 August, Scientific Society Press, Tokyo, 1992. Working document no. 123. Japan. p. 235-242. CIAT, Cali, Colombia. p. 390-399.
165 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 20
ACUTE POISONING IN TANZANIA: THE ROLE OF INSUFFICIENTLY PROCESSED CASSAVA ROOTS
N. L. V. Mlingi*
Abstract cyanogenic glucosides and cyanohydrins from the roots and In 1988, an outbreak of acute prevent poisoning are urgently needed poisoning occurred in a in this area. An intervention program drought-stricken district in southern has been established to develop an Tanzania. Studies carried out in the extension package for cassava area revealed that the victims had processing, and to make the high levels of thiocyanate, a cyanide population aware of the problem and metabolite found in the body’s plasma adopt more efficient processing and urine. The high dietary cyanide methods. came from consuming insufficiently processed roots of cassava, the only crop to survive the prolonged drought. Introduction Because of food scarcity, the customary, but lengthy, sun-drying of The advantages of cassava as a food peeled cassava roots was replaced by security crop in sub-Saharan Africa a repeated pounding and sun-drying usually outweigh the nutritional of peeled roots to obtain flour for drawbacks that sometimes make consumption the same day. An cassava appear an inferior food. experiment in one village showed that Drawbacks include low protein the principal source of dietary cyanide content of the roots, low energy comprised the high residual levels of density, and potential toxicity from the cyanohydrin (the intermediate presence of the cyanogenic glucosides breakdown product), which ranged linamarin and lotaustralin (Rosling, from 16 to 20 mg CN equivalent per 1987). kg dry weight. The shortened processing method adopted during the The amount of glucosides, mainly drought resulted in high glucoside consisting of linamarin (90%), can levels ranging from 3 to 879 mg CN reach 1,500 mg CN equivalent per kg equivalent per kg dry weight in the dry weight in fresh roots, particularly final products. Rapid, but more in those of bitter varieties grown for effective, tissue disintegration and their higher yields (Sunderesan et al., drying techniques that easily remove 1987). Environmental factors such as drought, pests, and diseases may increase the glucoside content (Gondwe, 1974). If the food security * Tanzania Food and Nutrition Center, Dar es provided by cassava is to have an Salaam, Tanzania. optimal impact on community health,
166 Acute Poisoning in Tanzania:... then the nutritional drawbacks must Despite cassava being extensively be avoided or balanced. used as food, reports of acute Supplementing cassava-based meals poisonings are rare. Most consumers with various protein sources can are aware of the potential toxicity and balance low protein content and low know how to detoxify the roots. Where energy density, and efficient cases of acute poisoning and other processing can solve toxicity effects have occurred, they were mainly problems. in populations suffering severe food shortages (Rosling, 1987). Lack of During processing, disintegrating scientific attention to such populations the root tissue releases an may also partly explain the scarcity of endogenous enzyme—linamarase— reporting. which hydrolyzes the glucosides to the corresponding intermediate products: A prolonged drought occurred in cyanohydrins (Figure 1). The Masasi District, southern Tanzania, in intermediate products at pH >6 1987/88, causing a severe food spontaneously decompose to volatile shortage that motivated people to hydrogen cyanide (HCN), which deviate from traditional cassava rapidly evaporates into the air or processing methods. The first visit to dissolves in water (Figure 1) (Cooke, the District, in September 1988, was 1978). during a “situation of emergency,” declared by authorities who had The glucosides, cyanohydrins, and received reports from many villages of HCN are collectively known as acute poisoning after consumption of cyanogens, and efficient processing cassava-based meals. can reduce them all to negligible levels. If insufficiently processed roots are consumed, cyanide exposure Materials and Methods can occur from glucosides or cyanohydrins breaking down in the The study area gut. The human body detoxifies cyanide by enzymatically converting it In 1988, Masasi District, Mtwara to the less toxic thiocyanate (or SCN), region, southern Tanzania, had a using sulfur as a substrate. Sulfur is population of 335,000, corresponding obtained from sulfur-containing to 38 inhabitants per square km. Most amino acids in the diet (Banea et al., of the soil in the District is a red loam, 1992). The thiocyanate is found in suitable for cassava and maize serum and urine, through which it is cultivation. The District has a excreted. Thus, cyanide exposure in unimodal rainfall that usually starts in humans can be estimated by late November and ends in May. determining thiocyanate in serum and Average annual rainfall is 940 mm and urine. temperatures vary from as low as 18 °C
Dissolves in Mainly water and/or CH CH3 3 nonenzymatic evaporates Enzymatic Slow at pH < 6-7 into the air
Glucose O C C≡N HO C C≡N > HC≡N
R1 or 2 R1 or 2
Figure 1. The breakdown of cyanogenic glucosides in cassava to produce hydrogen cyanide. R1 = CH3 for
linamarin; R2 = C2H5 for lotaustralin. 167 Cassava Flour and Starch: Progress in Research and Development in July to as high as 35 °C in Table 1. Dietary practices during food shortages December. in 35 interviewed households, Masasi district, southern Tanzania, 1988.
Cassava is a secondary staple in Foods consumed in Households Masasi but in difficult years becomes last 24 h the primary one. In neighboring (no.) (%) Newala District, cassava is the Cassava roots 35 100 primary staple and people from Wild vegetables 30 86 Masasi often beg or barter cassava Fruit (mainly mangoes) 29 83 roots and seedlings from Newala Cassava leaves 19 54 during periods of food shortage. An Maize 10 29 earlier rapid rural appraisal revealed Dried small fish 7 20 that prolonged sun-drying of peeled Legumes 6 17 roots was the main cassava processing method in Masasi (Seenappa and Mlingi, 1988).
from 28 men, 37 women, and 30 Key informants, focus-group children aged 5 to 14 years—a total of interviews, household surveys, and 95 subjects in the interviewed sample analysis households.
Local authorities and other key A year later, Mtandi and informants of Masasi District provided Chanikanguo villages were revisited. general information on the Of the previously studied households, agricultural and dietary situation in 12 volunteered to be briefly the District before and during the interviewed on diet and give urine drought in 1988. The district specimens, that is, 32 subjects authorities selected, for the study, the making up 9 men, 13 women, and villages of Mtandi, Chanikanguo, and 10 children. At the same time, Mumbaka, all 5 to 15 km from Masasi specimens of cassava flour used in the town and which had the highest interviewed households were collected. numbers of reported cases of acute Clinical records of the Ndanda Mission poisoning. Hospital and Masasi District Hospital were reviewed for cases of cassava In each village, the leaders, poisoning. In Mumbaka, six elders, and women were gathered for households that had reported acute focus-group interviews (Scrimshaw poisoning in 1988 were extensively and Hurtado, 1987) on agricultural reinterviewed on the symptoms and dietary practices. One 10-cell experienced. unit (an administrative structure with about 10 households) was selected in As a reference, thiocyanate was each village. In the 35 households determined in plasma and urine found in those units, the husband specimens collected from 201 adults of and/or wife were interviewed through both sexes, randomly selected, from a a formulated open-ended village in the Kilimanjaro region, questionnaire. This covered food northern Tanzania, where the dietary consumption over 24 h (Table 1), staple was banana, and cassava cassava cultivation and processing, consumption was rare. and occurrence of acute poisoning. To determine thiocyanate, an A cassava-processing experiment indicator of cyanide exposure, plasma was conducted in Mtandi village and urine specimens were collected during a follow-up study in 1988.
168 Acute Poisoning in Tanzania:...
Cyanogen levels were determined in bitter varieties of cassava but that, cassava flour obtained by two during the drought, roots from both shortened processing methods used varieties tasted more bitter than in during the food shortage. Roots from normal years. Among the interviewed 20 plants of a bitter variety, chimaje, households, 71% cultivated only bitter were harvested from the same field. varieties, while the rest cultivated both Roots were peeled and split lengthwise bitter and sweet. Of the six most to form 19 identical pairs of batches. commonly grown varieties, two, Under supervision, an elderly woman chimaje and limbanga, were identified processed one set of batches into as bitter; three—liumbukwa, kigoma, chinyanya flour and another set into and mba safi—as sweet; and the sixth small makopa (or dried root pieces), variety, mreteta, as either sweet (by which were later pounded into flour, as 58% of households) or as both sweet practiced during the food shortage. and bitter (23%).
All specimens collected were kept During the drought, the Prime frozen before analysis and thiocyanate Minister’s Office (PMO) promptly was determined according to Lundquist reacted to news of the food shortage by et al., (1979, 1983). Cyanogens in distributing about 400 t/month of flour samples were determined by an relief food, thus alleviating the threat enzymic assay method modified by of famine. But several households did O’Brien et al. (1991), permitting not receive relief because it was separate quantification of glucosides, insufficient, and used mainly to induce cyanohydrins, and HCN. people to cultivate communal fields in the most affected villages. Old and disabled people received free relief Results food.
Drought and food shortage Cassava processing
In normal years, cassava, maize, and In normal years, most cassava is sorghum dominate production in processed by direct sun-drying for higher areas while rice is restricted to 1 to 4 weeks, depending on sunshine. some lower swampy areas. Other food The roots are first peeled and left crops in the district include whole if small or split if large. The sweetpotatoes, cowpeas, and pigeon resulting dried root pieces are known peas. Cashews, groundnuts, and as makopa, and are either sold for bambara nuts are cultivated as cash cash or pounded into a flour used for crops. The area’s rainfall pattern making ugali, a stiff porridge. shows that rainfall was halved in the Legumes, small fish, cassava leaves agricultural year 1987/88, the period (kisamvu), or other green vegetables before the food shortage. Interviews constitute the relishes regularly eaten with key informants and focus groups together with cassava or maize ugali. confirmed that the drought from June 1987 to September 1988 caused the During the food shortage, the worst food shortages ever experienced normal processing method was in the district since 1966. Cassava replaced by two shortened methods. was the only crop which survived; Chinyanya was faster and more widely maize, rice, sorghum, and millet all used, according to the focus groups. failed. Peeled roots were pounded into pieces, sun-dried for some hours, then The focus groups revealed that repeatedly pounded and dried until a many families grow both sweet and flour was obtained within half to
169 Cassava Flour and Starch: Progress in Research and Development
1 day. The second method, “small in water, and another 18% fermented makopa,” involved cutting fresh roots peeled roots in covered heaps. into finger-sized pieces and drying them on hot rocks until they could be Acute poisoning and dietary pounded into flour. This method took cyanide exposure 1 or 2 days, depending on the sunshine. The relish used to Key informants stated that the acute supplement the ugali made from such poisoning following cassava-based short-processed roots, was limited to meals frequently occurred in the kisamvu during the food shortage. Masasi villages between March and September 1988. All those interviewed All households had consumed agreed that they had seen or heard cassava during the 24 h before the of villagers who were poisoned after interviews (Table 1). Although most eating cassava-based meals. Of the households consisted of farming 35 households interviewed in the families (91%), during the food second round, 80% confirmed that shortage, some relied on cassava either most family members had suffered bartered or given free of charge. Of the acute poisoning on one or more 29% of households that had consumed occasions. The pattern of symptoms, maize, almost a quarter had mixed it time of onset after meals, and duration with cassava flour to make ugali. All of poisoning, as determined by the households admitted they had made extensive interviews of households in some shortcuts in processing cassava Mumbaka village (Table 2) are by producing “small makopa” and 65% consistent with information obtained of households stated that they had from other interviews. used the chinyanya method. Clinical records for July 1988 Nevertheless, 9% of households showed that the Ndanda Mission fermented cassava by soaking the roots Hospital treated several outpatients
Table 2. Results of interviews of six households regarding acute poisoning in Mumbaka village, Masasi district, southern Tanzania, 1989.
Poisoning parameters Household code numbera
123 456
Number of persons affected 6 5 6 6 4 3 Number of times poisoned in 1988 3 3 10 10 1 1 Interval between meal and onset of symptoms (h) 1 4 1 6 2 2 Estimated duration of poisoning (h) 4 8 24 8 10 8 Cassava was processed into: Chinyanya yy y yyy “Small makopa”y Symptoms of poisoning: Vomiting y y y y y y Dizziness y y y y y y Nausea y y y y y y Palpitations y y y y y Weakness y y y y y Diarrhoea y y y y Headaches y y y y Difficulties in seeing y y y a. y = yes.
170 Acute Poisoning in Tanzania:... and admitted three patients for reexamined in the same month of cassava poisoning. The first was a 1989, a normal year, their mean 7-year-old girl who suffered urinary SCN was only 6% of the mean abdominal pain and vomiting after found the year before. All households eating bitter cassava. She recovered still consumed cassava daily but this the following morning without specific year the ugali was made from properly treatment. dried, normal-sized makopa (Essers et al., 1992). Two days later, a 4-year-old girl was admitted semiconscious and Cassava processing experiment dehydrated, but without fever. She had suffered a sudden onset of The two shortened methods, chinyanya intense vomiting caused by eating and “small makopa,” were used to pieces of cassava that were being process the 19 pairs of batches of split, dried. A routine neurological peeled roots from 20 cassava plants of examination was normal. She the same bitter variety from the same received antibiotic treatment against field, as described on p. 169. suspected aspiration pneumonia and parenteral fluid, and recovered within Each of the 19 batches processed 24 h. to chinyanya flour was pounded and sun-dried four successive times and Several days later, a 10-year-old sieved after each pounding to obtain boy was admitted unconscious after a flour. Each of the 19 batches sudden onset of poisoning symptoms processed into “small makopa” was from eating bitter cassava. Because split into small finger-sized pieces that antidotes were unavailable, he was were sun-dried on hot rocks and then treated with dextrose saline infusion pounded into flour at the end of the and cortisone but died 3 h later. day.
In July 1988, the Masasi District Table 4 compares the cyanogen Hospital also admitted three cases content of flours obtained in the with similar symptoms and history. experiment by the two shortened All recovered within 24 h. methods with that of flour samples collected from 12 households in 1989, Table 3 shows that, during the a normal year. Glucosides were very food shortage, the plasma SCN value high in the “small makopa” flour and was more than 10 times and the cyanohydrins were high in the urinary SCN more than 100 times chinyanya flour. The samples of higher in Masasi subjects than in “normal” flour had relatively high levels those from the Kilimanjaro village. of glucosides but very low cyanohydrin When 32 subjects in Masasi were content.
Table 3. Thiocyanate (SCN) levelsa in subjects from Masasi, southern Tanzania, who eat cassava, and subjects from Kilimanjaro, northern Tanzania, who eat banana.
SCN sample Cassava diet, Cassava diet, Banana diet, drought year normal year normal year (n = 95) (n = 32) (n = 201)
Plasma 335 ± 12 28 ± 4 Urine 1,120 ± 75 68 ± 9 7 ± 1 a. Values are given in µmol/L and as mean ± the standard error of mean.
171 Cassava Flour and Starch: Progress in Research and Development
Table 4. Cyanogen levels in cassava floura processed by three different methods, southern Tanzania.
Contents Processing experiment Household flour made from normal-sized Chinyanya “Small mapoka” mapoka, normal year (n = 19) (n = 19) (n = 12)
Glucosides 90 ± 17 768 ± 107 120 ± 70 (12-296) (121-1,837) (93-879)
Cyanohydrins 48 ± 5 15 ± 4 7 ± 2 (16-120) (0-61) (0-17)
Hydrogen cyanide 6 ± 1 7 ± 0.5 6 ± 0.5 (2-12) (5-10) (4-9)
Total cyanogens 144 ± 18 971 ± 107 133 ± 71 (56-336) (131-1,855) (8-901) pH 6.6 ± 0.1 6.9 ± 0.1 6.3 ± 0.2 (6.2-6.9) (6.6-7.2) (5.2-7.0)
Moisture (%) 13.5 ± 1 10.8 ± 0.2 10.6 ± 0.4 (6.0-23.6) (9.3-12.7) (9.5-14.4) a. Values are given as mean ± standard error of mean. Values in parentheses are ranges. Cyanogen values are measured as mg of CN equivalent/kg of dry weight.
Discussion this complicated analysis during our study, and relied on thiocyanate. Results confirm that most households Levels of this easily determined of the Masasi District suffered severe cyanide metabolite in the affected food shortage during March to population were among the highest December 1988, and depended almost ever reported in cassava eaters, entirely on cassava—the only crop to suggesting strongly that cyanide survive the drought. All interviewed caused the poisonings. The fact that households daily consumed ugali, the thiocyanate levels fell almost to most of it prepared from cassava flour normalcy the next year also supports made from short-processed roots. All the hypothesis of cyanide poisoning. acute poisonings resulted from eating ugali prepared from such flour, Cyanide especially chinyanya flour. Undoubtedly, thousands of people in In contrast to earlier assumptions the District were poisoned to some (Cheok, 1978), we concluded that degree during the food shortage. cassava poisoning is not the result of ingesting HCN. The reason is that General symptoms of the case HCN evaporates at 28 °C, thus rapidly patients suggested cassava poisoning, escaping during drying, as verified by which is characterized by an interval the low levels found in all flour of 1 to 4 h from meal to onset and analyzed. Further losses occur when symptoms usually clearing within boiling ugali. Cyanide is also rapidly 24 h (Cheok, 1978; Essers et al., absorbed from the stomach, whereas 1992). Cyanide, originating from the poisonings reported here occurred cyanogenic glucosides occurring one to several hours after ingestion. naturally in the roots, is presumed to The length of this interval suggests cause acute cassava poisoning. But that the cyanide exposure resulted blood cyanide levels were never from ingested cyanide precursors, documented. We could not perform such as glucosides or cyanohydrins,
172 Acute Poisoning in Tanzania:... that probably yielded cyanide in the Cyanohydrins small intestine. We believe that cyanide exposure Glucosides results mainly from consumption of cyanohydrins in ugali prepared from Ingested glucosides are an unlikely chinyanya flour. Total cyanogens source of cyanide exposure in the were higher in “small makopa” flour, Masasi population. The reasons are, but cyanohydrins were higher in first, experiments with animals chinyanya flour. indicate that ingested linamarin can be absorbed unchanged and excreted Very little is known about the fate intact in the urine (Barrett et al., of different forms of cyanogens during 1977). Ingesting linamarin will only digestion in humans. In the alkaline result in cyanide exposure if suitable environment of the small intestine, microbial glucosidases are present in cyanohydrins should rapidly the gut, a mechanism still not decompose to yield cyanide that is confirmed as occurring in humans. then absorbed. Our results support Second, poisonings were associated this hypothesis. The cyanohydrin mainly with consumption of level found in chinyanya can chinyanya flour, which had relatively potentially yield about 1 mmol of low glucoside levels. Third, the 1989 cyanide at the estimated daily subjects had low urinary thiocyanate consumption of about 0.5 kg. This levels, despite the high levels of quantity of cyanide matches the high glucosides found in the flour urinary thiocyanate level of 1 mmol/L collected from their households. An found during the poisonings. The adult’s estimated daily consumption next, normal, year, when the of 0.5 kg of normal, household, chinyanya method was not used, the cassava flour corresponds to cyanohydrin levels in household flour ingesting 2,000 µmol of potential were low, as were the urinary cyanide. The 68 µmol of thiocyanate thiocyanate levels. Those who per liter of urine constitutes only 3% consumed cassava in the normal year of this amount, indicating that or bananas had thiocyanate values ingested glucosides do not result in below 100 µmol/L, corresponding to cyanide exposure. the levels of thiocyanate found in nonsmokers1 in other countries The rapid drying of “small (Lundquist et al., 1979). makopa” in strong sunshine may result in high levels of glucosides, Effects of cyanide exposure probably because the heat destroys the linamarase enzyme or reduces Despite numerous cases of acute moisture content to a level that poisoning in many Masasi villages, inactivates this enzyme before tissue very few deaths were reported and disruption enables it to act on the we could only document one. glucosides. A daily consumption of Hospital-based reports of cassava 0.5 kg of “small makopa” corresponds poisoning give an impression of high to a potential cyanide yield of more mortality (Cheok, 1978; Tylleskar et than 300 mg, which is above the al., 1991), but anecdotal information lethal dose (Hall and Rumack, 1986). suggests low mortality in several other Thus, the low mortality observed outbreaks of cassava poisoning for suggests that glucoside ingestion is of which we could not find scientific minor importance for cyanide exposure from insufficiently 1. Cigarette smoke contains small quantities of processed cassava. cyanide.
173 Cassava Flour and Starch: Progress in Research and Development documentation. Although many epidemic. The highest incidences of subjects reached blood cyanide levels this disease have been found in at which symptoms of poisoning populations who exclusively occurred, few reached levels that were consumed insufficiently processed two to four times higher than lethal cassava for several weeks to months (Hall and Rumack, 1986). The small (Howlett et al., 1992; Tylleskar et al., number suggests that exposure to 1992). sudden high peaks of blood cyanide was rare. The rarity can be explained In conclusion, the 1988 acute if the levels causing symptoms are poisonings in Masasi resulted from partly reached by a cumulative effect consuming insufficiently processed from several meals, and partly caused cassava roots, and which therefore by a decreased cyanide-to-thiocyanate contained high residual amounts of conversion as the intake of sulfur cyanohydrins. Roots from bitter amino acids (which provides the cassava varieties can be safely eaten substrate for conversion) drops. A after effective processing. Even in the gradual cyanide release following shortened processing methods, meals would contribute to flat cyanohydrin levels may easily be exposure peaks that usually reach reduced by improving the levels causing only symptoms and, disintegration and drying techniques rarely, the higher levels causing used. death. Toxic effects from cassava may A different mechanism may also occur in several areas of eastern operate to reduce the mortality rate. Africa where bitter varieties have The metabolism of linamarin and its been introduced and where ineffective effects has not been studied in processing methods are used, humans. Some symptoms of acute especially during food shortages cassava poisoning may be caused by (Essers et al., 1992). However, non-lethal effects of absorbed, intact cassava’s agricultural potential may linamarin. If this hypothetical be used to improve food security with mechanism operates in parallel to a positive effect on nutrition and cyanide exposure, it may explain why health if attention is paid to its the frequency of diarrhoea seems potential nutritional drawbacks. higher than that reported for cyanide poisoning from other sources (Hall An ongoing program aims to and Rumack, 1986). provide practical measures to prevent further outbreaks of acute poisonings The epidemic paralytical disease, during food shortages. This involves konzo, characterized by abrupt onset making the authorities and the of spastic paraparesis, has been population aware of the faults in the attributed to high dietary cyanide ineffective processing methods exposure from insufficiently processed practiced in that area. The program cassava. We screened the population will then develop an extension in one village in Masasi for konzo package for cassava processing that and, as reported elsewhere (Tylleskar will use more efficient techniques, et al., 1991), found that the such as those for gari processing incidence of konzo was about 1 per from West Africa. The extension 1,000 people during the period of high package includes selecting the best cyanide intake. The minimal dietary and simplest message for the variation, provided by relief food, community, strategies to introduce probably protected the population new processing methods, and against a more extensive konzo approaches to be used.
174 Acute Poisoning in Tanzania:...
References O’Brien, G. M.; Taylor, A. J.; and Poulter, N. H. 1991. An improved enzymic assay method for cyanogens in fresh Banea, M.; Poulter, N.; and Rosling, H. 1992. and processed cassava. J. Sci. Food Shortcuts in cassava processing and Agric. 56:277-289. risk of dietary cyanide exposure in Zaire. Food Nutr. 14:137-143. Rosling, H. 1987. Cassava toxicity and food security: a review of health effects of Barrett, M. D.; Hill, D. C.; Alexander, J. C.; cyanide exposure from cassava and and Zitnak, A. 1977. Fate of orally of ways to prevent these effects. dosed linamarin in the rat. Can. J. Report to the African Household Physiol. Pharmacol. 55:134-36. Food Security Program, United Nations Children’s Fund (UNICEF). Cheok, S. S. 1978. Acute cassava poisoning International Child Health Unit, in children in Sarawak. Trop. Doc. Uppsala University, Uppsala, 8:99-101. Sweden. 40 p.
Cooke, R. D. 1978. An enzymatic assay for the Scrimshaw, S. C. M. and Hurtado, E. 1987. total cyanide content of cassava Rapid assessment procedures for (Manihot esculenta Crantz). J. Sci. nutrition and primary health care: Food Agric. 29:345-352. anthropological approaches to improving programmed effectiveness. Essers, A. J. A.; Alsen, P.; and Rosling, H. Reference series, vol. 11. Latin 1992. Insufficient processing of American Center, University of cassava induced acute intoxications California (UCLA), Los Angeles, CA, and the paralytic disease konzo in a USA. rural area of Mozambique. Ecol. Food Nutr. 27:17-27. Seenappa, M. and Mlingi, N. 1988. Household food security and the role Gondwe, A. T. D. 1974. Studies on of cassava: a case study from hydrocyanic acid content of some Tanzania. In: Nutrition and food local varieties of cassava and some security. Vol. 2. Proceedings of the traditional cassava products. East Afr. Third Africa Food and Nutrition Agric. For. J. 40:161-7. Congress, Harare, Zimbabwe, 5-8 September, 1988. p. 734-763. Hall, A. H. and Rumack, B. H. 1986. Clinical toxicology of cyanide. Ann. Emerg. Sunderesan, S.; Nambisan, B.; and Easwari, Med. 15:1067-74. A. 1987. Bitterness in cassava in relation to cyanoglucoside content. Howlett, W. P.; Brubaker, G. R.; Mlingi, N.; Indian J. Agric. Sci. 57:37-40. and Rosling, H. A. 1992. Geographical cluster of konzo in Tylleskar, T.; Banea, M.; Bikangi, N.; Fresco, Tanzania. J. Trop. Geogr. Neurol. L.; Persson, L-A.; and Rosling, H. 2:102-108. 1991. Epidemiological evidence from Zaire for a dietary aetiology of konzo, Lundquist, P.; Martensson, J.; Sorbo, B.; an upper motor neutron disease. and Ohman, S. 1979. Method for Bull. W. H. O. 69:581-90. determining thiocyanate in serum and urine. Clin. Chem. 25:678-81. ______; ______; ______; Poulter, N.; Cooke, R.; and Rosling, H. 1992. ______; ______; ______; and Cassava cyanogens and konzo, an ______. 1983. Adsorption of upper motor neuron disease found thiocyanate by anion-exchange resins in Africa. Lancet 339:208-11. and its analytical application. Clin. Chem. 29:403.
175 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 21
GARI, A TRADITIONAL CASSAVA SEMOLINA IN WEST AFRICA: ITS STABILITY AND SHELF LIFE AND THE ROLE OF WATER
N. Zakhia*, G. Chuzel**, and Dany Griffon*
Abstract consumed with milk (for breakfast) or added to hot sauces. Gari is a cassava semolina traditionally processed and widely As demand for gari from urban consumed in West Africa. Its markets is increasing, a better quality shelf-life is largely dependent on both product with an extended shelf-life is its water content and storage needed. The shelf-life of packed and temperature and relative humidity. stored gari largely depends on storage This paper deals with gari’s temperature and relative humidity, adsorption properties in relation to and on the product itself (moisture water availability at 15, 25, and content and water activity). These 30 °C. From the results, optimal parameters determine the rate of packaging conditions can be gari’s microbial and physicochemical estimated, thus providing an deterioration. The sorption isotherm, extended shelf-life for gari. that is, the equilibrium between water activity and moisture content of a foodstuff, is a good indicator of the Introduction product’s stability at different ambient temperatures and relative Gari is a cassava semolina humidities (Bandyopadhyay et al., traditionally prepared and widely 1980). consumed in West Africa. Gari processing consists of pressing the Our study used adsorption juice out of peeled and grated cassava isotherms to determine gari’s optimal roots for 2 to 4 days, allowing a shelf-life. Thus, we could propose a natural lactic fermentation to take set of packaging recommendations to place. The fermented mash is then ensure better storage of gari in the cooked in an open clay vessel until tropics. the starch gelatinizes sufficiently (Chuzel, 1989; Zakhia, 1985). Gari is a “ready-to-use” food, generally Materials and Methods
Samples of traditional Togolese gari (about 8% w.b. water content) were * CIRAD/SAR, Montpellier, France. collected from a small factory near ** CIRAD/SAR, stationed at the Faculdade de Lomé and packaged in sealed Ciências Agronômicas (FCA), Universidade Estadual Paulista (UNESP), São Paulo, polyethylene bags. They were sent to Brazil. Montpellier, France, and stored at
176 Gari, A Traditional Cassava Semolina in West Africa:...
Table 1. Experimental data for adsorption equilibrium of gari at 15, 25, and 35 °C (± SD) with salt sources and references.
Salt 15 °C 25 °C 35 °C
Equilibrium Moisture Equilibrium Moisture Equilibrium Moisture relative content relative content relative content humidity (% d.b. ± SD) humiditya (% d.b. ± SD) humidity (% d.b. ± SD)
LiCl 0.119b 5.2 ± 0.4 0.110 4.8 ± 0.1 0.112b 4.4 ± 0.3 c d 5.9 ± 0.2 CH3COOK 0.234 7.4 ± 0.4 0.224 6.7 ± 0.3 0.230 b b MgCl2 0.333 8.1 ± 0.4 0.330 7.6 ± 0.2 0.320 7.3 ± 0.3 c e 8.6 ± 0.2 K2CO3 0.431 9.1 ± 0.2 0.428 8.6 ± 0.3 0.410 NaBr 0.607c 11.4 ± 0.7 0.577 11.0 ± 0.2 0.545c 10.3 ± 0.6 b d SrCl2 0.741 15.2 ± 0.8 0.708 14.3 ± 0.2 0.680 13.7 ± 0.8 NaCl 0.755c 15.4 ± 0.5 0.753 16.1 ± 0.2 0.751f 16.6 ± 0.7 KCl 0.856b 20.7 ± 0.9 0.843 20.3 ± 0.6 0.829c 20.8 ± 1.2 b g BaCl2 0.911 24.5 ± 0.8 0.902 26.7 ± 0.6 0.894 26.8 ± 1.2 a. Stokes and Robinson, 1949. b. Acheson, 1965. c. Greenspan, 1977. d. Rockland, 1960. e. Griffin, 1944. f. Clarke and Glew, 1985. g. Baxter and Cooper, 1924.
2 °C until evaluation. Adsorption were then sprayed with a solution of isotherms were determined at 15, 25, sodium azide (0.5%) to inhibit the and 35 °C, using the standard growth of microorganisms at high method recommended by the Water water activities (aw > 0.8). They were Activity Group (WAG) of the European placed in dishes resting on trivets Union (EU)1 (Wolf et al., 1985). standing in jars of salt solutions. The Equipment used comprised nine, sealed jars were then submerged in sealed, glass jars, containing an insulated water bath, the saturated salt solutions ranging from temperature of which was controlled aw 0.1 to 0.9 (Table 1). This aw range to within ± 0.2 °C. is required practice for predicting the shelf-life of dried packaged products Equilibrium time was 21 days, as (Chirife et al., 1979). recommended by WAG’s standard
(i.e., 7 days for aw < 0.6 and 14 days
In France, before measurements for aw > 0.6), and in accord with the were taken, 3 g of gari samples were equilibration time required for predried over phosphorus pentoxide cassava mash (Gevaudan et al.,
(P2O5) for 10 days at about 20 °C 1989). Equilibrated samples were (ambient temperature) to lower their oven-dried (103 °C, 24 h) in triplicate water content to a minimum. They to determine moisture content.
The WAG uses the GAB (Guggenheim-Anderson-De Boer) model, which is believed to be the 1. The Water Activity Group conducts the best for providing equations for
project “COST 90 bis” as part of the program describing food isotherms up to aw 0.9 for European Cooperation in the Field of (Bizot, 1983; Van den Berg, 1985). Science and Technical Research, sponsored by the former European Economic The GAB equation is as follows Community, now the European Union. (Labuza et al., 1985):
177 Cassava Flour and Starch: Progress in Research and Development
a Results and Discussion w = αa² + βa + γ (1) X w w Adsorption isotherms where: Table 1 and Figure 1 show the average values and standard K 1 α=() −1 deviations of the equilibrium moisture XCm contents for the water activities studied at 15, 25, and 35 °C, and 1 2 β=()1 − their fitted GAB isotherms. XCm
At low water activities (aw < 0.6), γ= 1 the experimental curves agree with XKCm .. the sorption theory, that is, at
constant aw, an increase of X = water content (% d.b.) temperature causes a small decrease of moisture content. At high water activities (0.7-0.9), moisture content Xm = percentage of water content corresponding to the increases with rise in temperature. occupation of all primary The three calculated isotherms adsorption sites by one water intersect at the following points:
molecule. “Xm” is also called the “monolayer.” isotherms 15 °C and 25 °C
where X = 13.0% and aw = 0.66 C = the Guggenheim constant. isotherms 15 °C and 35 °C N where X = 11.5% and a = 0.59 C = C exp [(H1 - Hm)/RT] w isotherms 25 °C and 35 °C
K = a correction factor for the where X = 9.5% and aw = 0.48 multilayer molecules. K = KN
exp [(H1 - Hq)/RT]
H1 = the heat of condensation of pure water vapor 30
Hq = the total heat of sorption of the multilayer water molecules 20
Hm = the total heat of sorption of the monolayer
α O/100 g dry matter) 10
The GAB model’s coefficients , Moisture content 2 β, and γ were determined for each temperature by using a nonlinear, (g H least-square regression as recommended by Schär and Rüegg 0 0 0.2 0.4 0.6 0.8 1.0 (1985). The values of GAB
Water activity (aw) constants Xm, C, and K were also calculated. The confidence of fit was judged by the relative root Figure 1. Adsorption isotherms of gari at three mean square error (% RMS). temperatures. Experimental points are means of triplicates. = 15 °C; = 25 °C; = 35 °C.
178 Gari, A Traditional Cassava Semolina in West Africa:...
The crossing of isotherms at high content (for aw between 0.5 and 0.7) water activities with increasing initiate a “collapse” that makes the temperature has already been soluble starch (amorphous fractions observed in some foods and may and branched segments) leach out. result from the product’s chemical This increases the number of composition and its treatments (e.g., available adsorption sites (glucose heating, drying, and residues) and explains why gari pregelatinization). Other foods becomes more hygroscopic at higher showing this phenomenon are temperatures and water activity. sucrose and fructose (Loncin et al., Moreover, the degree of starch 1968), potato slices (Mazza, 1982), damage in gelatinized starchy carrots (Mazza, 1983), Jerusalem products is measured by the artichoke (Mazza, 1984), and sultanas solubility and swelling indices at (Saravacos et al., 1986). The 30 °C, which depend on the ability of explanation is that some sugars starch to absorb water (Anderson et increase their solubility with al., 1969). temperature, thus binding more water at higher temperatures and Slade and Levine (1988) and increasing the equilibrium moisture Orford et al. (1989) have also content. discussed the physicochemical effect of water, acting as a plasticizer of the The technological treatments amorphous regions in the starch involved in gari production (grating, native granule, on the temperature of fermentation, and squeezing) induce the vitreous transition that occurs damage to about 3% to 6% of the during native starch gelatinization. cassava starch (Zakhia, 1985). Only the water included in the starch During roasting, the starch is heated granule (about 10% w.b.) is involved in the presence of water, but the in this process; the vitreous transition initial moisture content of about temperature decreases sharply with 1 g g-1 (d.b.) of cassava mash does not increasing water content. This allow the starch to completely plasticizing effect could also explain gelatinize (Chuzel, 1989; Gevaudan et the observed adsorption behavior of al., 1989). But crystallinity is lost gari. The amorphous matrix of gari, and extensive swelling of the starch which is partially plasticized at room granules occurs. A complex temperature by excess water (> 12% metastable network forms, consisting d.b.), would become more plastic if of amorphous regions (containing the temperature increased to 35 °C. plasticizing water) and hydrated The mobility of chains is then microcrystalline regions that had not enhanced and the free volumes inside dissolved during the partial the polymer increase. As these free gelatinization and which serve as volumes may absorb more water, the junction zones (Levine and Slade, sorption sites are then more available. 1988). All these factors strongly affect the polymer-water interactions Gari storage (Radosta et al., 1989). In tropical countries, high relative The sorption mechanism for humidity and temperature make starch is almost entirely governed by long-term storage very difficult. So active sites, that is, the glucose predicting the shelf-life of packaged residues of the starch polymer (Hill gari in terms of its storage conditions and Rizvi, 1982). We suggest, and quality becomes important. The therefore, that increases in both Heiss and Eichner (1971a; 1971b) temperature (to 35 °C) and water model allows calculation of the
179 Cassava Flour and Starch: Progress in Research and Development
potential storage time based on a Ws = Weight of the product (kg of critical aw for a particular system dry matter in the package). under given storage conditions. This model equation is: S = Slope of the product isotherm (assumed linear over the range
−− between “Xe” and “Xc”). Θ = ln ((XXei ) /( XX ec )) c (2) KAWxso(/ )(P/) S Using the Heiss and Eichner model, we estimated the shelf-life of where: gari packaged in 1-kg polyethylene 2 -6 bags (A = 0.124 m , Kx = 2.28 10 kg Θ -2 -1 -1 c = Potential shelf-life of the H2O.m .Pa .day ) at three product (time in days for the temperatures (15, 25, and 35 °C) and packaged product to suffer four initial moisture contents (6%, microbial and biochemical 8%, 10%, and 12% d.b.) (Table 2). As deterioration with loss of ambient storage conditions, we sensory quality). considered a relative humidity of 0.9 (which is the safe storage borderline
Xe = Equilibrium moisture content humidity) and an aw of 0.7 (which is -1 (g g , d.b.) of the product (if it the safe storage borderline aw is left in contact with the generally used for most products) atmosphere outside the (Pixton, 1982). Adeniji (1976)
package). “Xe” depends on observed a significant growth of temperature, relative humidity mould in gari stored at 27 °C, in a and on the product adsorption relative humidity of 0.7 and having an isotherm. equilibrium content of 14.5% (d.b.).
For aw 0.7, our sorption curves at
Xc = Safe storage moisture 15, 25, and 35 °C give 14.0%, 14.2%, content of the product (g g-1, and 15.3% (d.b.) as equilibrium d.b.), that is, the moisture moisture contents (Table 2). These content corresponding to the values agree with those of Adeniji
safe storage borderline aw. (1976). Moisture contents around
“Xc” is calculated for the 14% (d.b.) allow gari to maintain a
borderline aw by successive crispness that consumers greatly iterations from the GAB appreciate (Chuzel, 1989; Ekundayo, regression equation until the 1984). difference between two
calculated “Xc” is lower than Moisture contents before
0.01. packaging (Xi) are those generally found in local gari sold in tropical
Xi = Initial moisture content of the markets. lkediobi and Onyike (1982) product when it is packaged mention moisture contents ranging (g g-1, d.b.). from 4% to 19% (d.b.). The crossing-over of adsorption isotherms
Kx = Permeability of the package to described above leads to the following moisture vapor paradox: gari stored at 35 °C seems to -2 -1 -1 (kg H2O.m .Pa .day ). be better than that stored at 25 °C for a moisture content of 12% (d.b.).
Po = Vapor pressure at storage This moisture content is usually temperature (in Pa). obtained with traditional gari processing (Chuzel, 1989), although A = Surface area of the package storage time was less than 1 month (m2). under the given conditions.
180 Gari, A Traditional Cassava Semolina in West Africa:...
Table 2. Estimated shelf-life (days) for safe storage of gari at aw 0.7 at four initial moisture contents (d.b) and three storage temperatures.
Initial moisture content (d.b.) Equilibration temperature (°C)a
15 (14.0) 25 (14.2) 35 (15.3)
6 181 90 57 8 166 85 52 10 140 73 45 12 89 24 30
a. Values in parentheses are equilibrium moisture contents (d.b.) for aw 0.7 (from experimental adsorption isotherms).
We also focused on the packed in cardboard boxes for both permeability of packaging materials. physical convenience and to prevent Polyethylene, especially the oxidation and reaction to light. high-density type, tends to inhibit water vapor transfer, but is permeable Further research should be to oxygen and carbon dioxide, which carried out to determine the safe may oxidize gari or cause loss of its storage water activity in the tropics, aromas. Polypropylene is less taking into account the initial permeable to water vapor and oxygen, microbial flora of cassava roots and but, because it is more expensive the local quality requirements for gari than polyethylene, it is less suitable quality, that is, color, crispness, for storing gari as a daily foodstuff for flavor, and food customs. low-income consumers.
References Conclusions Acheson, D. T. 1965. Vapor pressure of Gari processing modifies the saturated aqueous salt solutions. structure of native cassava starch so In: Wexler, A. (ed.). Humidity and moisture, vol. 3. Reinhold, NY. that, at high water activity, it p. 521-530. becomes more hygroscopic as temperature increases. Our study Adeniji, M. O. 1976. Fungi associated with pointed out a “collapse” (not yet the deterioration of gari. Niger. J. observed in other starchy products), Plant Prot. 2:74-77. caused by the partial gelatinization Anderson, R. A.; Conway, H. F.; Pfeiffer, of gari starch. The GAB regression V. F.; and Griffin, E. L. 1969. equation was adequate for fitting Gelatinization of corn grits by roll and sorption isotherms of gari. extrusion cooking. Cereal Sci. Today 14(1):4-7.
The shelf-life of gari was Bandyopadhyay, S.; Weisser, H.; and Loncin, theoretically estimated for three M. 1980. Water adsorption storage temperatures (15, 25, and isotherms of foods at high 35 °C) at a relative humidity of 0.9 temperatures. Lebensm. Wiss. & (which is usual in the tropics). For a Technol. 13:182-185. low-cost storage of at least Baxter, G. P. and Cooper, W. C., Jr. 1924. 3 months at about 30 °C, we The aqueous pressure of hydrated recommend packaging gari at an crystals. II. Oxalic acid, sodium initial moisture content of about 8% sulfate, sodium acetate, sodium (d.b.) in polyethylene bags. The carbonate, disodium phosphate, barium chloride. J. Am. Chem. Soc. bags should be sealed and tightly 46:923-933.
181 Cassava Flour and Starch: Progress in Research and Development
Bizot, H. 1983. Using the “GAB” model to Ikediobi, C. O. and Onyike, E. 1982. The use construct sorption isotherms. In: of linamarase in gari production. Jowitt, R.; Escher, F.; Hallstrom, B.; Process Biochem. 17(4):2-5. Meffert, H. F. T.; Spiess, W. E. L.; and Vos, G. (eds.). Physical properties of Labuza, T. P.; Kaanane, A.; and Chen, J. Y. foods. Applied Science Publications, 1985. Effect of temperature on the London, UK. p. 43-54. moisture sorption isotherms and the water activity shift of two dehydrated Chirife, J.; Boquet, R.; and Iglesias, H. 1979. foods. J. Food Sci. 50:385-391. The mathematical description of water sorption isotherm of foods in Levine, H. and Slade, L. 1988. Water as a the high range of water activity. plasticizer; physicochemical aspects Lebensm. Wiss. & Technol. of low moisture polymeric systems. 12:150-152. Water Sci. Rev. 3:79-185.
Chuzel, G. 1989. Etude des traitements Loncin, M.; Bimbenet, J. J.; and Lenges, J. technologiques intervenant lors de la 1968. Influence of the activity of transformation du manioc en gari. water on the spoilage of foodstuffs. Ph.D. dissertation. Ecole nationale J. Food Technol. 3:131-142. supérieure agronomique de Montpellier (ENSAM), Montpellier, Mazza, G. 1982. Moisture sorption isotherms France. 195 p. of potato slices. J. Food Technol. 17:47-54. Clarke, W. E. and Glew, D. N. 1985. Evaluation of the thermodynamic ______. 1983. Dehydration of carrots: function for aqueous sodium chloride effects of pre-drying treatments on from equilibrium and calorimetric moisture transport and product measurements below 154 °C. J. Phys. quality. J. Food Technol. 18:113-123. Chem. Ref. Data 14(2):429-610. ______. 1984. Sorption isotherms and Ekundayo, C. A. 1984. Microbial spoilage of drying rates of Jerusalem artichoke packaged gari in storage. Microbios (Helianthus tuberosus). J. Food Sci. Lett. 26:145-150. 49:384-388.
Gevaudan, A.; Chuzel, G.; Didier, S.; and Orford, P. D.; Parker, R.; Ring, S. G.; and Andrieu, J. 1989. Thermophysical Smith, A. C. 1989. Effect of water as properties of cassava mash. Int. J. a diluent on the glass transition Food Sci. Technol. 24:637-645. behavior of malto-oligosaccharides, amylose and amylopectin. Int. J. Biol. Greenspan, L. 1977. Humidity fixed points of Macromol. 11:91-96. binary saturated aqueous solutions. J. Res. Natl. Bur. Stand. A. Phys. Pixton, S. W. 1982. The importance of Chem. 81 A(1):89-96. moisture and equilibrium relative humidity in stored products. Trop. Griffin, R. C. 1944. Technical Association of Stored Prod. Inf. 43:16-29. the Pulp and Paper Industry (TAPPI). TAPPI Data Sheet 109-109a. Radosta, S.; Schierbaum, F.; Reuther, F.; NY. and Anger, H. 1989. Polymer-water interaction of maltodextrins, part 1. Heiss, R. and Eichner, K. 1971a. Moisture Water vapour sorption and desorption content and shelf-life. I. Food Manuf. of maltodextrin powders. Starch/ 46(5):53-56. Stärke 41(10):395-401.
______and ______. 1971b. Moisture Rockland, L. 1960. Saturated salt solutions content and shelf-life. II. Food Manuf. for static control of relative humidity 46(6):37-38, 41-42. between 5 °C and 40 °C. Anal. Chem. 32(10):1375-1376. Hill, P. E. and Rizvi, S. S. H. 1982. Thermodynamic parameters and Saravacos, G. D.; Tsiourvas, D. A.; and storage stability of drum dried peanut Tsami, E. 1986. Effect of temperature flakes. Lebensm. Wiss. & Technol. on the water adsorption isotherms of 15(4):185-190. sultana raisins. J. Food Sci. 51(2):381-383.
182 Gari, A Traditional Cassava Semolina in West Africa:...
Schär, W. and Rüegg, M. 1985. The Wolf, W.; Speiss, W. E. L.; and Jung, G. evaluation of G.A.B. constants from 1985. Standardization of isotherm water vapor sorption data. Lebensm. measurements. In: Simatos, D. and Wiss. & Technol. 18:225-229. Multon, J. L. (eds.). Properties of water in foods. Nato Asi series, Slade, L. and Levine, H. 1988. Non- no. 90. Martinus Nijhoff, Dordrecht, equilibrium melting of native the Netherlands. p. 661-679. granular starch. Part I. Temperature location of the glass transition Zakhia, N. 1985. Etude de I’operation de associated with gelatinization of cuisson-séchage du gari; mémoire A-type cereal starch. Carbohydr. ingénieur. Ecole nationale supérieure Polym. 8:183-208. des industries agricoles et alimentaires, Section Régions Stokes, R. H. and Robinson, R. A. 1949. Chaudes (ENSIA-SIARC), Montpellier, Standard solutions for humidity France. 97 p. control at 25 °C. Ind. Eng. Chem. 41:2013.
Van den Berg, C. 1985. Development of B.E.T.-like models for sorption of water on foods theory and relevance. In: Simatos, D. and Multon, J. L. (eds.). Properties of water in foods. Nato Asi series, no. 90. Martinus Nijhoff, Dordrecht, the Netherlands. p. 119-131.
183 SESSION 4:
BIOCONVERSION AND BYPRODUCT USE Fermentation in Cassava Bioconversion
CHAPTER 22
FERMENTATION IN CASSAVA BIOCONVERSION1
M. Raimbault*, C. Ramírez Toro**, E. Giraud***, C. Soccol.†, and G. Saucedo††
Introduction STD2 Program of the European Union (EU), otherwise known as “Improving Cassava fermentation is traditionally the Quality of Traditional Foods practiced in the tropics. But both Processed from Fermented Cassava” technology and product (Raimbault, 1992; Saucedo et al., characteristics differ according to 1990). region and sociocultural conditions: gari in East and West Africa, When producing gari, lactic chikwangue or fufu in Central Africa, acidification of cassava is rapid and and sour starch in Latin America. But detoxification is sometimes they have in common the aim to incomplete. Controlling through eliminate the poisonous cyanide inoculation would improve quality. components and conserve cassava by For fufu or chikwangue, retting is lactic acidification. essential for texturing and detoxifying the cassava. Lactic acid fermentation The essential role of lactic acid is heterolactic, operating in bacteria in the three products was association with secondary alcoholic demonstrated by studies carried out and anaerobic fermentation to by the Institut français de recherche produce alcohol and organic acids scientifique pour le développement en such as butyrate, acetate, and coopération (ORSTOM) through the propionate that develop special aromatic and organoleptic characteristics. As for gari, fermentation for sour starch (especially in Colombia and Brazil) is * Institut français de recherche scientifique homolactic, but takes 3 or 4 weeks. pour le développement en coopération Amylolytic lactic acid bacteria have (ORSTOM), stationed in Cali, Colombia. ** Laboratorio de Bioconversión, Departamento been isolated from chikwangue by de Procesos Químicos y Biológicos, Facultad ORSTOM scientists and from sour de Ingeniería, Universidad del Valle, Cali, starch by CIRAD scientists. Colombia. *** ORSTOM, Montpellier, France. † Laboratório de Procesos Biotecnologia, A. Brauman isolated a new strain, Departamento de Tecnologia Química, Lactobacillus plantarum A6, which was Faculdade de Engenharia, Universidade described by Giraud et al. (1991). Its Federal de Paraná, Brazil. †† Departamento de Biotecnología, Universidad physiological and enzymological Autónoma Metropolitana (UAM), Iztapalpa, characteristics for cultivation on Mexico. cassava starch media, amylase 1. No abstract was provided by the authors. production, and biochemical
187 Cassava Flour and Starch: Progress in Research and Development properties have now been described Solid-State Fermentation of (Giraud et al., 1992; 1993a; 1993b). Cassava and Starchy Products ORSTOM scientists have been researching solid fermentation For more than 15 years, an ORSTOM cultivation of fungi on cassava and group has worked on a solid-state amylaceous components for more than fermentation process for improving 10 years. Soccol et al. (1994) showed the protein content of cassava, that protein enrichment is possible by potatoes, bananas, and other starchy cultivating various strains of Rhizopus, commodities used for animal feed. even on crude, nongelatinized cassava Fungi, especially from the Aspergillus flours. Saucedo et al. (1992a; 1992b; group, are used to transform starch 1992c) studied, at the ORSTOM and mineral salts into fungal proteins Laboratory, Montpellier, the growth (Oriol et al., 1988a; 1988b; Raimbault and alcohol fermentation of cassava and Alazard, 1980; Raimbault and starch in solid-state fermentation, Viniegra, 1991; Raimbault et al., using a highly promising amylolytic 1985). Table 1 shows the overall yeast. changes in composition between the initial substrate and final products. Swedish and African researchers Through such techniques a have described the beneficial effects of cassava-fermented product with an lactic acid fermentation on the 18%-20% protein content (dry matter prophylactic and keeping basis) was obtained. characteristics of those traditional foodstuffs made from fermented More recently, Soccol et al. cassava, maize, and mixed cereals, (1993a; 1993b), also at the ORSTOM and of baby foods. These foods tend Laboratory, obtained good results to increase children’s resistance to with the Rhizopus fungi, of special diarrhoea. interest in traditionally fermented foods. In particular, they studied the All these studies are being effect of cooking before fermentation continued in new projects comprising on the availability of starch, protein the EU-STD3 Program. Other EU content, and the rate of starch’s studies are being conducted on bioconversion into protein (Table 2). cassava quality, environment, physical They found that a selected strain of processing, and transformation at a Rhizopus oryzae could transform low industrial scale to take advantage uncooked cassava, which contains of the economic and commercial only 1.68% protein, into a fermented opportunities in Latin America. cassava containing 10.89% protein.
Table 1. Effects of Aspergillus niger on protein and sugar contents of different starches (percentage of dry matter) after 30 h of fermentation in solid-state culture.
Substrate Initial composition Final composition
Proteins Sugar Proteins Sugar
Cassava 2.5 90 18 30 Banana 6.4 80 20 25 Banana waste 6.5 72 17 33 Potato 5.1 90 20 35 Potato waste 5.1 65 18 28
188 Fermentation in Cassava Bioconversion
Table 2. Growth of Rhizopus oryzae in solid-state cultivation on cassava granules after various cooking treatments.
Treatmenta Dry matterb Total sugarc Proteinsc
Initial Final Initial Final Initial Final
I 60.90 46.48 80.01 46.78 1.20 11.69 II 59.18 45.35 84.11 60.72 1.61 12.40 III 57.95 42.12 82.44 52.57 1.56 13.93 IV 55.63 43.88 82.49 56.62 1.47 11.89 V 45.57 37.88 82.04 56.62 1.68 10.89 a. Treatment: I = Cassava autoclaved for 30 min at 120 °C, frozen, dried, and ground II = Cassava flour (40% water) autoclaved for 30 min at 120 °C III = Cassava flour (30% water) autoclaved for 30 min at 120 °C IV = Cassava flour (30% water) vapor cooked for 30 min at 100 °C V = Untreated crude cassava flour b. g/100 g total weight. c. g/100 g dry matter.
SOURCE: Soccol et al., 1994.
Table 3 shows results of amylase (1971) was adopted and a good biosynthesis in solid or liquid correlation coefficient for the culture, using raw or cooked calibration curve was obtained. cassava. The amount of Table 4 shows the effect of thermic glucoamylase was 10 to 15 times treatment and microwaves on starch higher in solid than in liquid culture, gelatinization in cassava flour (water and higher in raw starch medium content typically lower than 10%). than in cooked cassava. Where water content was very low, gelatinization was also low. This work is being continued in the EU-STD3 Program at the The same thermic treatment of Bioconversion Laboratory of the dry cassava flour eliminated the Universidad del Valle, Cali, natural microflora contained in raw Colombia. It focuses on simplifying flour, from 109 bacteria/g of dry flour cassava processing by learning more to fewer than 103 bacteria/g after about the specificity of Rhizopus heating the flour for 30 min at strains in degrading the raw starch 90 °C. With gelatinization limited to granule. But clean flours of raw less than 5% under such conditions, cassava are needed. The common obtaining clean, raw cassava flour is flours of cassava contain too much possible in the laboratory. natural microflora to allow microbial studies with fungi; they must first be Figures 1 and 2 show the effects sterilized and (unfortunately) of various physical and thermic gelatinized. Ramírez et al. (1994) treatments on the bacteria content of developed raw cassava flour with a cassava flour. Cassava flour will be very low content of bacteria and used as a solid substrate for fungi, and little gelatinization. cultivating Rhizopus strains, and to compare the capacity of selected To measure gelatinization, the strains to grow on raw or gelatinized simple method of Wotton et al. cassava starch.
189 Cassava Flour and Starch: Progress in Research and Development
Gluco- Protein
a
α−
Solid-state culture
cultivated on cassava granules.
55.30 10.60 178.40 46.22 12.30
Gluco- Protein
Rhizopus oryzae
α−
98.00 108.00 11.40 167.00 37.00 13.80
9.60
9.30 55.00 70.00 12.60 170.00 47.00 14.10
Gluco- Protein
a
α−
145.40 3.30
Gluco- Protein
Raw cassavacassava Cooked Raw cassavacassava Cooked
α−
amylase amylase (g/100 g amylase amylase (g/100 g amylase amylase (g/100 g amylase amylase (g/100 g
(U/g DM) (U/g DM) DM) (U/g DM) (U/g DM) DM) (U/g DM) (U/g DM) DM) (U/g DM) (U/g DM) DM)
Table 3. Effect of cooking and type of culture on the growth and amylases of various strains of
Strain ofRhizopus culture Liquid-state
28627 76.00 7.80 4.00
a. DM = dry matter; U = enzyme units.
SOURCE: Soccol et al., 1994. 28168 42.20 9.60 3.90 157.20 3.10 10.00 39.30 34612 40.40 7.30 4.60 168.50 5.70
190 Fermentation in Cassava Bioconversion
Table 4. Effect of temperature and microwaves on starch gelatinization of cassava flour.
Temperature Time Gelatinization rate (%)a (min) Exp. 1 Exp. 2 Exp. 3 Mean
Test 1 75.439 84.063 88.911 82.80 (80% gel.)
Test 2 25.411 26.184 29.702 27.10 (20% gel.) 80 °C 60 3.529 3.444 2.714 3.23 85 °C 30 3.529 3.357 3.487 3.46 85 °C 3.444 3.486 3.444 3.46 90 °C 30 3.572 3.444 3.572 3.53 90 °C 60 9.454 9.064 9.107 9.21 95 °C 30 6.961 5.546 5.803 6.10 100 °C 30 4.965 4.602 4.001 4.52 105 °C 30 6.961 5.503 5.301 5.92 120 °C 30 4.816 4.730 4.473 4.67 140 °C 30 4.773 3.100 3.100 3.66 160 °C 30 3.529 3.487 4.301 3.77
Autoclaving 15 3.572 3.100 4.301 3.66 (121 °C)
Microwaves 5 2.886 2.410 2.842 2.71 (Pot. 70)
Microwaves 5 2.971 2.242 2.242 2.49 (Pot. 100)
Microwaves 15 3.879 3.057 3.915 3.62 (Pot. 30)
a. Exp. = Experiment. Mean is across the experiments.
10 9 10 10 123123
121323
123123 9 8 10 10 123123
123123
123123 8 10 107 123123 123123
123123 7 10 106 123123 123123
123123 106 105 121323 123123
123123 105 104 123123123 123123123
123123123 104 3 123123123123 10 123123121323 123
123123123123123 123123123
123123123123123123123121323
Viable bacteria (n/g of flour) 3 Viable bacteria (n/g of flour) 2 10 10 123123123123121323123123123
123123123123123123123123123
123123123123123123123123123123123 102 101 0 30 60 90 120 0 80 85 90 95 100 105120140 160 180 Duration of treatment (minutes) Temperature (°C)
Figure 1. Total microflora (plate count analysis) Figure 2. Effect of temperature on bacterial in cassava flour, according to population in cassava flour. treatment. ( = ultra-violet radiation; = microwaves; = 80 °C; = 85 °C; = 90 °C.)
191 Cassava Flour and Starch: Progress in Research and Development
Lactic Acid Fermentation The first strain of Lactobacillus of Cassava plantarum to be described as having very high amylolytic capacity was Lactic acid fermentation is important obtained from fermented cassava by for many traditional fermented foods, A. Brauman in the Congo. Detailed silage, and animal feed, and for physiological and biochemical recycling agroindustrial byproducts. characterization of this new strain Because of its acid, bacteriostatic, is expected to be published soon by and bactericidal properties, E. Giraud. fermentation prevents microorganisms, whether parasitic, Mbugua and Njenga (1991) and saprophytic, or pathogenic, from Svanberg (1991a; 1991b), working breaking down vegetable material. in Tanzania and at the Uppsala University, respectively, have In tropical countries, lactic reported on the effect of lactic acid fermentation not only plays an fermentation on the pathogen important role in the traditional microflora content of traditional transformation of starchy foods, African foods. such as cassava, but also in the transformation and conservation of Some of their results are other foods, and fish and its reported in Table 5 and Figure 3, byproducts. Two types of lactic which show how lactic acid fermentation exist: bacteria reduce the number of food-poisoning pathogens such as (1) Homolactic, when more than species of Staphylococcus, 80% of total acidity and Salmonella, and Shigella, and metabolites formed consists of Escherichia coli. High levels of such lactic acid, and pathogens are sometimes found in (2) Heterolactic, when the traditional foods after processing percentage of acetic acid, under unhygienic conditions, propionic acid, and ethanol is especially those for malting maize more significant, and lactic acid during the rainy season in parts of represents 50%-80% of total tropical Africa. acidity. Lactic fermentation of Lactic bacteria produce two types traditional foods reduces pathogenic of lactic acid: L(+) and D(-). Only the bacteria from 108 to 103. The same L(+) form is assimilated by humans. authors also found a significant correlation between the resistance Previous studies, realized during of young children to diarrhoea and the EU-STD2 Program in 1988-1991 eating acidified gruels. (Raimbault, 1992), consisted of improving traditional fermented food We are bioconverting, through made from cassava in Africa and probiotics and bactericides, cassava Latin America. Three kinds of flour and starch containing traditional foods were considered: amylolytic lactic acid bacteria to gari, chikwangue, and sour starch. isolate new strains from traditional We demonstrated the essential role foods. At the same time, we are of lactic acid bacteria in all broadening knowledge on the traditional processes. cultivation of lactic acid bacteria in starchy substrates. We hope such Amylolytic lactic bacteria were information will help elaborate new isolated from fermented cassava. food and feed products.
192 Fermentation in Cassava Bioconversion
Table 5. Effect of lactic acid fermentation on the content of pathogenic bacteria in traditional fermented foods in Africa.
Time (h) Log number of bacteria/g food
Control Nonfermented, Fermented food acidified food Flour Gruel (nonviable) (viable)
Shigella flexneri 0 6.8 6.7 6.4 6.0 3 6.6 5.8 5.1 4.0 7 7.0 4.2 5.5 3.3 24 7.0 4.1 3.7 2.7 Salmonella typhimurium 0 8.5 8.1 8.3 7.7 3 8.0 6.7 6.0 7.1 7 7.9 5.3 4.4 6.3 24 8.9 4.0 2.0 2.0
SOURCE: Lorri and Svanberg, 1988.
10 production. This may be because, first, cassava cultivation yields 9 relatively few, commercially significant byproducts, compared with, for 8 example, sugarcane which yields 7 enormous quantities of bagasse, a valuable source of energy for 6 distillation. Second, cassava starch needs to be hydrolyzed into sugar for 5 bioconversion into ethanol by the common Saccharomyces cerevisiae.
Log viable bacteria (n/g gruel) 4 This implies an additional, costly step.
3 For cassava to be an economically 0 102030405060 viable energy source, its processing Time (h) costs must be reduced. Solid-state Figure 3. Evolution of pathogenic bacteria during fermentation is one, simple, and new the lactic fermentation of uji, a method of reducing costs: the use of an fermented cassava gruel (after Mbugua amylolytic yeast that eliminates and Njenga, 1991). ( = Staphylococcus aureus; = Salmonella typhimurium; hydrolysis. = Escherichia coli; = Shigella dysenteriae.) At the ORSTOM Laboratory, Saucedo et al. (1992a; 1992c) developed a new process for the solid Alcoholic Fermentation of culture of an amylolytic yeast, Cassava and Starch Products Schwanniomyces castelii (Figure 4). The main advantage of this technique Cassava is a potential producer of is its continuous recuperation of ethanol, considering its potentially ethanol in a cold trap condenser. The high yields and low costs. Yet few gas produced in the reactor is pumped reports concern the industrial throughout the system, thus ensuring application of cassava for ethanol its continual removal from the medium
193 Cassava Flour and Starch: Progress in Research and Development
and limiting its toxic effects on the potential of cassava as a substrate yeast’s metabolism. The results for ethanol production. The solid- obtained by Saucedo et al. (1992a; state technique has to be carefully 1992b; 1992c) were promising, but considered. Results obtained with the technology and feasibility of the the fungus Rhizopus koji are process for commercial operation particularly significant. The need further research. potential of Schwanniomyces is also interesting because amylolytic yeast Table 6 shows the results would be easier to control at the obtained by various authors on the small-scale industrial level.
Pump
Continuous extraction of ethanol Cold trap condenser
Reactor
Ethanol
Column to humidify gas
Figure 4. Producing ethanol through solid-substrate fermentation of cassava starch. The reactor contains a solid support impregnated with a starchy suspension and inoculated with the fermentation agent, an amylolytic yeast known as Schwanniomyces castelii. The resulting gas is pumped to a condenser where ethanol is extracted. The residual gas is sent to a humidifier.
Table 6. Comparison of various processes for ethanol production from cassava in liquid or solid substrate.
Process Hydrolysis Sugar Ethanol Recovered Theoretical (g/L) (g/L) (g/L) (%)
Liquid substrate, using S. cerevisiae a, b + 145 72.50 72.50 83.2
Solid substrate, using S. cerevisiae b, c + 165 41.73 41.73 65.0
Solid substrate, using Rhizopus koji d - 200 110.00 110.00 83.0
Solid substrate, using Schw. castelii e, f - 300 68.40 212.60 64.0 a. Saraswati, 1988. b. S. = Saccharomyces. c. Jaleel et al., 1988. d. Jujio et al., 1984. e. Schw. = Schwanniomyces. f. Saucedo et al., 1992a.
194 Fermentation in Cassava Bioconversion
Conclusions on ______; Gosselin, L.; and Raimbault, M. Bioconverting Cassava and 1992. Degradation of cassava linamarin by lactic acid bacteria. Potential Products Biotechnol. Lett. 14(7):593-598.
To bioconvert cassava starch and ______; ______; Marín, B.; Parada, flour to elaborate new products, J. L.; and Raimbault, M. 1993a. ORSTOM, CIRAD, and collaborating Purification and characterization of an extracellular amylase from institutes are emphasizing two lactobacillus plantarum strain A6. approaches: solid-state fermentation, J. Appl. Bacteriol. 75:276-282. and lactic acid fermentation. ______; ______; and Raimbault, M. The first is of great interest 1993b. Production of a Lactobacillus plantarum starter with because of its potential to simplify linamarase and amylase activities for processes and reduce costs, and its cassava fermentation. J. Sci. Food large reactor volume. Both Rhizopus Agric. 62:77-82. and Schwanniomyces (or other amylolytic) yeasts can be used in a Jaleel, S. A.; Srikanta, S.; Ghildyal, N. P.; and Lonsane, B. K. 1988. solid-state cultivation process. This Simultaneous solid phase implies a three-phase reactor with a fermentation and saccharification of solid fiber support, a liquid phase cassava fibrous residue for containing the substrate in production of ethanol. Starch/Stärke suspension and salts, and a gaseous 40(2):55-58. phase for exchanging volatile Lorri, W. S. M. and Svanberg, U. 1988. components, that is, oxygen, water, Improved protein digestibility in and ethanol. cereal based weaning foods by lactic acid fermentation. Harare, Zimbabwe. In lactic acid fermentation, we are investigating the culture control Mbugua, S. K. and Njenga, J. 1991. Antimicrobial properties of fermented of amylolytic lactic acid bacteria in UJI as a weaning food. In: Westby, A. mixed and composite starters able to and Reilly, P. J. A. (eds.). Traditional remain competitive in a natural, African foods: quality and nutrition. nonaxenic environment. The International Foundation of Science prophylactic role of lactic acid (IFS), Sweden. p. 63-67. bacteria is also of great interest. Oriol, E.; Raimbault, M.; Roussos, S.; and Viniegra-González, G. 1988a. Water Finally, we are studying and water activity in the solid state microorganisms able to degrade fermentation of cassava starch by native cassava starches without Aspergillus niger. Appl. Microbiol. need of gelatinization, as in in Biotech. 27:498-450. natural biotransformation and biodegradation. We will also ______; Schetino, B.; Viniegra-González, G.; and Raimbault, M. 1988b. Solid study the amylolytic capacity of state culture of Aspergillus niger on Rhizopus spp., yeasts, and lactic acid support. J. Ferment. Technol. bacteria. 66:1-6.
Raimbault, M. 1992. Etudes physiologiques et génétiques des bactéries References lactiques dans les fermentations traditionnelles du manioc. Final Giraud, E.; Brauman, A.; Kéléke, S.; Lelong, report CEE/STD2, no. TS2A-00226. B.; and Raimbault, M. 1991. Institut français de recherche Isolation and physiological study of scientifique pour le développement en an amylolytic strain of Lactobacillus coopération (ORSTOM), Montpellier, plantarum. Appl. Microbiol. France. p. 1-53. (Internal Biotechnol. 36:379-383. document.)
195 Cassava Flour and Starch: Progress in Research and Development
______and Alazard, D. 1980. Culture ______; ______; and Raimbault, M. method to study fungal growth in 1992c. Maintenance of heat and solid fermentation. Eur. J. Appl. water balance as scale-up criterion Microbiol. Biotechnol. 9:199-209. for production of ethanol by Schwanniomyces castelii in solid ______and Viniegra, G. 1991. In: state fermentation system. Process Chahal, D. S. (ed.). Modern and Biochem. 27:97-107. traditional aspects of solid state fermentation in food, feed and fuel Soccol, C.; Iloki, I.; Marín, B.; and from biomass. p. 153-163. Raimbault, M. 1994. Comparative production of alpha-amylase, ______; Revah, S.; Pina, F.; and Villalobos, glucoamylase and protein P. 1985. Protein enrichment of cassava enrichment of raw and cooked by solid substrate fermentation using cassava by Rhizopus strains in molds isolated from traditional foods. submerged and solid state J. Ferment. Technol. 63(4):395-399. fermentations. J. Food Sci. Technol. 31:320-332. Ramírez, C.; de Stouvenel, A.; and Raimbault, M. 1994. Effect of physical treatments ______; Marín, B.; Roussos, S.; and on microflora content in cassava flour. Raimbault, M. 1993a. Scanning Poster presented at the International electron microscopy of the Meeting on Cassava Flour and Starch, development of Rhizopus arrhizus held in January 1994 at Cali, on raw cassava by solid state Colombia. fermentation. Micol. Neotrop. Apl. 6:27-39. Saraswati. 1988. The experience of pilot plant of ethanol from cassava in Indonesia. ______; Rodríguez, J.; Marín, B.; Regional Workshop on Upgrading of Roussos, S.; and Raimbault, M. Cassava/Cassava Wastes by 1993b. Growth kinetics of Rhizopus Appropriate Biotechnologies, Bangkok, arrhizus in solid state fermentation Thailand, 1987. Thailand Institute of of treated cassava. Biotechnol. Scientific and Technological Research, Tech. 7(8):563-568. Bangkok, Thailand. p. 41-49. Svanberg, U. 1991a. Lactic fermentation of Saucedo, G.; González, P.; Revah, S.; Viniegra, cereal-based weaning gruels and G.; and Raimbault, M. 1990. Effect of improved nutritional quality. In: Lactobacilli inoculation on cassava Westby, A. and Reilly, P. J. A. (eds.). (Manihot esculenta) silage: Traditional African foods: quality fermentation pattern and kinetic and nutrition. International analysis. J. Sci. Food Agric. Foundation of Science (IFS), 50:467-477. Sweden. p. 53-60.
______; Lonsane, B. K.; Navarro, J. M.; ______. 1991b. The potential role of Roussos, S.; and Raimbault, M. fermented cereal gruels in 1992a. Potential of using a single reduction of diarrhoea among fermenter for biomass build-up, starch young children. In: Westby, A. and hydrolysis and ethanol production: Reilly, P. J. A. (eds.). Traditional solid state fermentation system African foods: quality and nutrition. involving Schwanniomyces castelii. International Foundation of Science Appl. Biochem. Biotechnol. 36:47-61. (IFS), Sweden. p. 33-38.
______; ______; ______; ______; Wotton, M.; Weedon, D.; and Munck, N. and ______. 1992b. Importance of 1971. A rapid method for estimation medium pH in solid state fermentation of starch gelatinization in processed system for growth of Schwanniomyces foods. Food Technol. Aust. castelii. Lett. Appl. Microbiol. 23:612-614. 15:164-167.
196 Cassava Lactic Fermentation in Central Africa:...
CHAPTER 23
CASSAVA LACTIC FERMENTATION IN CENTRAL AFRICA: MICROBIOLOGICAL AND BIOCHEMICAL ASPECTS
A. Brauman*, S. Kéléke**, M. Malonga***, O. Mavoungou***, F. Ampe†, and E. Miambi***
Summary cyanogenic compounds (e.g., concentration decreased from Retting is a lactic fermentation during 400 ppm in fresh cassava to 20 ppm which cassava roots are soaked for in fermented mash); (2) a significant long periods in water. Despite the lysis of cassava cell walls due to the importance of this fermentation, no simultaneous action of endogenous kinetic study of it has been pectin methylesterase and bacterial undertaken. Our study therefore pectin lyase; and (3) the production of examined the biological and physical organic acids (C2 to C4), mainly lactate changes of cassava roots during and butyrate, that contribute to the retting to provide a basis for its typical flavors of chikwangue and possible mechanization. fufu.
The study was carried out to In the study, most microflora (1) enumerate and characterize the involved in retting were facultative, main microorganisms of the process; anaerobic, fermentative bacteria, (2) determine the evolution of among which lactic bacteria were physicochemical parameters during predominant. From the second day of retting; and (3) measure the fermentation, endogenous production of organic products and Lactobacillus species were totally some principal enzyme activities. supplanted by Leuconostoc mesenteroides and Lactococcus lactis. Retting can be characterized by Anaerobic bacteria such as three essential transformations of the Clostridium butyricum were also found roots: (1) a degradation of endogenous and seemed responsible for initiating butyrate production. Yeasts played no significant role, but their increasing number at the end of the * Institut français de recherche scientifique process (Candida species) probably pour le développement en coopération influenced the conservation of end (ORSTOM), Paris, France. products. ** Laboratoire de microbiologie, Direction générale de la recherche scientifique et technique (DGRST), Brazzaville, Congo. Despite the significant number of *** Laboratoire de biologie cellulaire, Faculté des amylolytic bacteria (105-106 b/ml), the sciences, Université Marien-N’Gouabi, amylase activity found in the retting Brazzaville, Congo. † Laboratoire de microbiologie et de juice came from the roots and biotechnologie, ORSTOM, stationed in disappeared after 48 h of Brazzaville, Congo. fermentation. The main enzymes of
197 Cassava Flour and Starch: Progress in Research and Development this process were cassava pectin Significant differences exist in methylesterase, bacterial pectinase, retting processes throughout Central and endogenous linamarase. Africa and even in the Congo. Peeled or unpeeled roots are retted in rivers, The pH became stable at about standing water, large barrels of water, 4.5 after 48 h and the partial oxygen or even buried in soil. The pressure dropped to 0.2 mg/L after fermentation temperature varies with 10 h. season and location. Such differences, combined with the low These results suggested that reproducibility of the local processors, retting is a typical heterolactic lead to a variability in quality and fermentation with a significant taste of cassava foods (Trèche and production of butyrate. Massamba, n.d.a).
To increase the quality of these Introduction traditional products and provide a basis for the possible mechanization Processed cassava (Manihot of the process, the European Union esculenta Crantz) is eaten in West (EU) Program-STD2, known as and Central Africa in such forms as “Improving the Quality of Traditional gari, lafun, fufu, chikwangue, and Foods Processed from Fermented tapioca. In the Congo, the world’s Cassava” was set up in 1990 in second largest cassava consumer Central Africa and South America. after Zaïre (Trèche, n.d.), cassava Our laboratory was to describe the roots account for 47% of the calorie mechanisms of root transformation intake (Trèche and Massamba, during retting with a view to n.d.b). optimizing product quality and fermentation speed. The two main products associated with fermented cassava are fufu and In this paper, we present the main chikwangue. The former is a flour results obtained during this EU obtained from sun-dried cassava program, describe the microbiological mash that is pulverized. This flour and biochemical evolution throughout may be mixed with boiling water and the process, and define the origin served in bowls with sauce and fish or (vegetal or microbial) of the main meat. Chikwangue, a cassava bread, enzymes. is obtained after multiple postfermentation steps, including defibering and pugging (Trèche and Material and Methods Massamba, n.d.a). Origin of plant material Both products require a fermentation in which the roots soak Cassava roots (Manihot esculenta var. for 3 to 6 days in tap water. During MM 86, or ‘Ngansa’) were harvested this process, cyanogenic compounds near Brazzaville, Congo, 18 months are eliminated, flavor compounds after planting. are elaborated, and the roots soften (Okafor et al., 1984; Oladele Retting procedures Ogunsa, 1980). Softening is indispensable for further root About 100 kg of washed and peeled processing but the mechanisms roots were placed in a barrel and the involved are not yet fully volume made up to 50 L with rain understood. water. A second barrel, filled only
198 Cassava Lactic Fermentation in Central Africa:... with rain water, was used as control Bacterial enumeration for physicochemical measurements
(T °C, pH, pO2). Samples were taken Lactic acid bacteria (l.a.b.). every 12 h for the first 2 days and The l.a.b. were enumerated on MRS then every 24 h until retting was agar medium (de Man et al., 1960), completed. supplemented with 0.1% of aniline blue. In each petri dish, 0.1 ml of Sample preparation for bacterial appropriate root sample dilution was enumeration covered with medium and kept at 45 °C. Enumeration was carried out Sampling was carried out by after a 48-h incubation at 30 °C. randomly selecting six root sections, Subcultures were further purified by which were then cut into 0.5-cm repeated plating. cubes and mixed under sterile conditions. Of this mixture, 60 g Strains were differentiated into were extracted and diluted in 540 ml various bacterial groups by the of sterile, peptonized water (dilution following tests: microscopy 10-1). The solution was then mixed in examination, gram reaction, catalase a Blendor (Turnmix ME 88, test, and oxygen metabolism SOFRACA, France) and serially (fermentative or oxidative) test in soft diluted in sterile, peptonized water for MRS agar. Strains which were gram aerobic counts and in anaerobic positive, catalase and oxidase Hungate tubes containing sterile, negative, nonmotile rods or cocci, and reduced water, flushed with 20% CO2 colored by aniline blue were and 80% N2 for anaerobic counts. considered as lactic bacteria.
Methods of bacterial quantification Glucose- and lactate-fermenting bacteria. These bacteria (g.f.b. and Two types of enumeration were l.f.b., respectively) were enumerated performed: “most probable number” on a basal medium that contained the (MPN) enumeration and plate counts equivalent of 2 g/L glucose or 5 g/L on solid medium. The MPN method of lactate (used as a carbohydrate was used to either ascertain the source); 0.5 g/L of trypticase and growth of fermentative and yeast extract; 0.5 g/L of cysteine HCl pectinolytic bacteria or count the (used as a reductive agent); 0.1 g/L metabolites produced during growth of sodium acetate; 0.005 g/L of on appropriate media for anaerobic, resazurine; 20 ml of Widdel mineral lactate-using bacteria. For each MPN solution (Widdel and Pfennig, 1984); determination, four successive and 1 ml of Widdel trace element dilutions of root samples were solution (Widdel and Pfennig, 1984). inoculated in three or four tubes per dilution. Results were calculated The Hungate technique (Hungate, according to the McCready tables 1969), modified for using syringes (McCready, 1918). (Macy et al., 1972), was used throughout the study. After boiling, For plate counts, 0.1 ml samples the medium was cooled under a of appropriate dilutions were continuous flow of oxygen-free N2, inoculated in triplicate on agar adjusted to a pH of 7.2 with NaOH medium in plates. All the plates solution, and distributed were incubated at 30 °C and the anaerobically into Hungate tubes. number of colony-forming units The medium was sterilized for 35 min determined after 48 or 72 h of at 110 °C. Before inoculation, 1% of incubation. Na2S-9H2O (5%) was added as a
199 Cassava Flour and Starch: Progress in Research and Development reductive agent to each tube. sample was added to a Waring Inoculations were performed with blender and mixed with 120 ml syringes filled with oxygen-free N2, distilled water at low speed for 15 s using a gas manifold. and at high speed for 1 min. The mixture was then filtered through a Yeast. A potato-dextrose agar GF/A filter and the volume made up medium (PDA, DIFCO Laboratory) was to 200 ml with distilled water. prepared, containing 0.05 g/L of Extracts were taken in duplicate at chloramphenicol and with a final pH 0 h, 48 h, and at the end of retting. of 3.5, adjusted with tartaric acid Acidity was titrated with 0.01 M (10%). The agar’s surface was then NaOH. dried. From an appropriate microbial dilution, 0.1 ml was spread, in Biochemical analysis triplicate, on plates containing the medium. The plates were then Enzyme assays. A sample of incubated for 72 h at 30 °C. 40 g of cassava mash was added to a Subcultures were further purified by Waring blender, together with 80 ml repeated plating on PDA. Isolates of 0.1 M citrate buffer (pH = 6.5) and were characterized to the genus level, the mixture homogenized. The and Api tests (API 5030 strips mixture was held overnight at 4 °C Biomerieux, France) were used to and centrifuged at 12,000 g for determine fermentation carbohydrate 30 min. The supernatant was sources. lyophilized and resuspended in 1/10 volume of citrate buffer. Physicochemical parameters βββ-glucosidase activity. This Penetrometry index. was measured with a chromogen, Penetrometry was used to indicate p-nitrophenol-β-d-glucopyranoside, root softening during retting. A at 20 mM in 0.1 M of Na-phosphate previous study showed that a buffer (pH = 6.8) for 1 h at 25 °C. penetrometry index of 15 mm/5 s The reaction was stopped by adding corresponded to the end of retting as an equal volume of 0.2 M sodium it is traditionally evaluated (Brauman borate (pH = 9.8), and p-nitrophenol et al., n.d.). A penetrometer (PNR was determined with a 10-SUR, Berlin) was used to measure spectrophotometer at 400 nm (Hosel the consistency of the roots. Every and Bartz, 1975). 10 h, and for each experiment, six root sections were randomly chosen. Linamarase. This was assayed Penetrometry depth was estimated with linamarin as substrate and by with six repetitions for each root measuring the appearance of CN- section. (Giraud et al., 1992). To 400 µl of extract, 100 µl of 50 mM linamarin The pH and partial oxygen in 0.1 M citrate buffer (pH = 6.0) pressure of the retting juice. Every were added. At regular intervals, 10 h, 50 ml of retting juice was 50 µl aliquots were added to 50 µl of extracted to test the pH (measured 0.1 M NaOH to stop the reaction, with CG 838 pH-meter from SCHOTT and stored at 4 °C. Cyanide was Geräte, Germany) and estimate liberated by adding 50 µl of 0.1 M µ partial oxygen pressure (measured H2SO4 and 850 l distilled water to with OXI 91 from WTW, Germany). each aliquot, and was measured with a spectroquant kit (Merck, The pH and partial oxygen Darmstadt, Germany). One unit of pressure of the roots. A 20-g linamarase was defined as the
200 Cassava Lactic Fermentation in Central Africa:... amount of enzyme that released buffer (pH = 5.0). Penetrometer 1 µmol of CN- per minute. readings were estimated after 24 h and 48 h at 30 °C. Activity of pectinesterase (PE; pectin pectylhydrolase, Cellulase, amylase, and EC 3.1.1.11). This was assayed by xylanase activities. These activities titrating 1 ml of extract in 1% pectin were also assayed at 37 °C and pH of at 30 °C (Grindsted RS400-DM 74%), 5.8, using the Somogyi procedure and in 0.1 M NaCl and 1 mM NaN3. (Somogyi, 1945). The substrates were pH was increased to 7.0 with 0.01 M microcrystalline cellulose (100 mg) NaOH. One unit corresponds to the and xylan (18 mg/ml). neutralization of 1 µmol of COO-/min. Other analytical methods Polygalacturonate lyase (PGL) activity. PGL activity was assayed Total and free cyanides were assayed by the Starr et al. (1977) procedure. by the Cooke et al. method (1978). This assay does not differentiate Protein was determined with a between endo-PGL (poly (1,4-α-d- modified Lowry procedure (Bensadoun galacturonide) lyase, EC 4.2.2.2) and and Weinstein, 1976). exo-PGL (poly (1,4-α-d-galacturonide) exolyase, EC 4.2.2.9). One unit of Organic compounds PGL corresponds to the formation of 1 µmol of one unsaturated bond in Sugars, volatile fatty acids (VFA), and galacturonide between C4 and C5. lactate and ethanol concentrations in the roots were determined by Polygalacturonase (PG; poly high-performance liquid (1,4-ααα-d-galacturonide) chromatography (HPLC) of the glycanohydrolase, EC 3.2.1.15). supernatant, as described by Giraud This was assayed by viscometry. To et al. (1991). The resulting columns 40 ml of 1% pectin in 100 mM of (BioRad Laboratories, Richmond, acetate buffer (pH = 4.7), 0.5 ml of California) were: extract was added. The rate of reduction in viscosity was measured (1) Fast carbohydrate column for at 25 °C in a viscometer (Haake monosugars analysis (100 x 7, model; VT 500, rotation: 150.93 s-1 8 min) with 0.6 ml flow of milliQ and system MV-MV1). One unit water (pH = 6.0) at 70 °C; corresponds to the release of 1 µmol (2) Aminex HP 42 A (300 x 7.8 min of hexose/min. Total activities are Biorad) for polyosides analysis expressed as units per 100 g of with 0.3 ml flow of milliQ water cassava. (pH = 6.0) at 70 °C; (3) Aminex HP x 87H column with Action of pectic enzymes in 0.8 ml/min flow of H2SO4 6 mM at vivo. Sterilized slices of cassava were 60 °C. inoculated with 50 µl of enzyme extract or 5 µl of purified pectolytic Results and Discussion enzymes (endopolygalacturonase P-5146 from Aspergillus niger; Kinetic studies of retting pectolyase P-3026 from A. japonicum; and pectinesterase P-0764 from We now present the results of our orange peel) (Sigma, Saint-Quentin global study of lactic fermentation. Fallavier, France). The inoculated Kinetic parameters such as total and slices were placed in sterile beakers fermentative microflora, containing 10 ml of 0.01 M of citrate physicochemical parameters, and
201 Cassava Flour and Starch: Progress in Research and Development
12 7 5
10 4
8 6 3
6 pH (mg/L) 2 2 pO 4 5 Penetrometry index 1 2
0 4 0 01234
Time (days)
Figure 1. The evolution of physicochemical parameters during retting. ( = pH; = pO2; = penetrometry index.)
substrates and metabolites produced 300 have been measured throughout the process. These results are the mean of seven rettings performed in barrels 200 under the same conditions.
Evolution of physicochemical ppm parameters 100
The main physicochemical parameters were assayed throughout the process (Figure 1). The partial 0 oxygen pressure dropped to well 01 23 45 below 1 mg/L after 10 h and the pH Time (days) became stable (at 4.5) within 48 h. Conversely, root softening, indicated Figure 2. Total cyanide evolution. by the penetrometry index, appeared ( = linamarin; = cyanhydrines + free cyanides; = free cyanides.) after 2 days of fermentation and evolved exponentially. This process seems to require anaerobic and acidic conditions to proceed. Microscopic basis) in fresh cassava to 20 in the examination shows that the cassava fermented mash (Figure 2). In all cell walls were extensively disrupted assays, total cyanogens were at the end of the process, almost eliminated (90%). These demonstrating the attack of results demonstrated that, under depolymerizing enzymes. the standard conditions of local transformations in Central Africa, The concentration of endogenous detoxification occurred normally cyanogenic compounds decreased without need of an additional from 300 mg/kg as HCN (dry matter process.
202 Cassava Lactic Fermentation in Central Africa:...
Evolution of substrates and The main organic acid produced metabolites was lactate. However, significant levels of ethanol, acetate, and The main substrates degraded butyrate were also found (Figure 4). (Figure 3) were oligosaccharides They seem to be generated mostly by (fructose, glucose, and saccharose). the heterolactic fermentation of the The low level of polyosides generated oligosaccharides present in the by starch degradation (e.g., cassava roots, except for butyrate, maltotriose and maltose) underline which could have come from an the weak degradation of the starchy anaerobic fermentation mediated by mass during retting. Saccharose Clostridium species. Butyrate seems to be the main substrate concentration could vary from 0.4 to degraded by the fermentative 2.5 g/100 of dry matter in different microflora. fermentations carried out under the
4.5 123
123
123 4.0 123 123
123 123
123 123
3.5 123 123 123
123 123 123
123 123 123 3.0 123 123 123 123 123 123
123 123 123
123 123 123 2.5 123 123 123 123 123 123
123 123 123
123 123 123
2.0 123 123 123
123 123 123 123 123 123 123
123 12 123 123 123
1.5 123 123 121233 12 123 123 123 123
123123 121323 121323123 12 123
12312123 121321233 121321323 12123 123
123 123 123 1.0 12312 123123 121323 12123 123 12 123 123 123 12312 121323 121323 12123 121233 12 123 123 123 12312 123123 121323 12123 123123 12123 123 123 123 123
12312 121323 121323 12123 121323 12123 0.5 123 123 123 123 123 123
12312312 121323123 121321323 12312123 121323123 12312123
12312312 123123123 123123123 12312123 123123123 12312123 Conc. g per 100 of dry matter 0 0 1224364862 Time (hours)
Figure 3. Oligo- and monosaccharide evolution during retting. ( = maltotriose; = maltose; 12 12 123 123 = saccharose; 12 = glucose; 12 = fructose.)
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0
1234
123123 1231234 123 123 1231234 123123 1234123 0.5 1234 1234 123 123 1231234 121323 1231423 1234 1234 123 Conc. g per 100 of dry matter 1234123123 12341231234 1234123123 12341231234 1234123123 1231234123 0 0 1224364862
Time (hours)
123 123 123 123 Figure 4. Organic acids and alcohol evolution during retting. ( 123 = butyrate; = ethanol; 123
123
123 = acetate; = lactate.)
203 Cassava Flour and Starch: Progress in Research and Development same conditions. Because of their anaerobic spore formers (Clostridium organoleptic qualities, butyrate and species). To evaluate this population, lactate seem to be the most typical enumeration was done anaerobically products of this process. on lactate because (1) lactate is the major substrate found in retting; and Microflora evolution (2) it is not used as a substrate by the l.a.b. Surprisingly, the results of this Fermentative and lactic enumeration showed that the microflora. In the enumerations, population of lactate-fermenting only fermentative bacteria were bacteria remained constant and at counted because retting was seen as low levels (103 b/g of DM) throughout largely anaerobic (Figure 1). The the retting (Figure 5). The presence of fermentative microflora evolved butyrate and acetate in the positive during the first 2 days of fermentation tubes, and the isolation of strictly and remained stable to the end. The anaerobic, sporulating, gram-positive total fermentative microflora rods with the same fermentation represented by the glucose-fermenting pattern as Clostridium butyricum, bacteria was dense, reaching 1012 b/g confirmed that Clostridium species are after 48 h of fermentation. The next present in retting. However, their role most predominant flora were the in the process remains to be studied l.a.b. (Figure 5), reaching 104 to because of their reduced numbers in 108 b/g of DM on fresh roots. The the enumeration and lactate does not variation of endogenous l.a.b., seem to be their natural substrate in composed mainly of Lactococcus and retting. heterolactic Lactobacillus species, did not influence the evolution of l.a.b. Yeasts. The only flora that during fermentation. appeared after 48 h of fermentation and still developed until the end of Lactate-fermenting bacteria. retting were yeasts. Their One metabolite formed during metabolisms allow them to grow at fermentation is butyrate (Figure 4). the low pH imposed by the l.a.b. This compound is a typical product of Their numbers remained low during carbohydrate fermentation by the fermentation (about 103 b/g of
14
1234
1234
123 1234 1234
123 1234 1234
12 123 1234 1234
123 1234 1234
123 1234 1234
123 1234 1234
123 1234 1234
10 123 1234 1234
1234 123 1234123 1234
1234 123 1234123 12341234
1234 123123 1234123 12314 234
1234 123 1234 1234 123 123 1234
8 1234 123 1234 1234 123 123 1234 1234 123 1234 1234 1234 123 123 1234 1234 123 1234 1234
1234 123 123 1234 1234 123 1234 1234
12341234 123123 1234123 12341234
6 12341234 123123 1234123 12341234
12314 234 123123 1234123 12314 234
1234 1234 123 1234 1234 1234 123 123 1234
1234 1234 123 1234 1234 123 1234 123 123 1234123 1234 1234 123 1234 1234 1231234 1234123 1231234 123 1234123 4 1234 1234 123 1234 1234 1231234 1234123 1231234 123 1231423 1234 1234 123 1234 1234
12341231234 12341234123 1231231234 12341231234 12341234123
Log. b/g of dry matter 12341231234 12341234123 1231231234 12341231234 12341234123
12341231234 12314 234123 1231231234 12341231234 12314 234123
2 1234 1234 123 1234 1234 1231234 1234123 1231234 1231234 1234123
1234 1234 123 1234 1234 1231234 1234123 1231234 1231234 1234123 1234 1234 123 1234 1234 1213234 1231423 1213234 1213234 1231423 1234 1234 123 1234 1234
1231234 1234123 1231234 1231234 1234123 0 1234 1234 123 1234 1234 024486072
Time (hours)
123
123 Figure 5. Evolution of fermentative microflora during retting. (123 = glucose-fermenting bacteria; 12 123 12 = lactic acid bacteria;1 23 = lactate-fermenting bacteria; = yeast.) 12 123
204 Cassava Lactic Fermentation in Central Africa:...
DM), suggesting that they do not Origin of softening. No play a significant role in retting. softening was obtained in sterile When the retting finished, the yeasts fermentation (Figure 6). High covered the entire water surface and endogenous pectin methyl esterase became the main flora of the activities were found in cassava postretting stage. Their increasing extracts from both fermentations numbers at the end of the process (Figure 7). Depolymerizing enzymes, (mostly Candida species) may endopolygalacturonase (active at therefore influence the conservation low pH), and pectate lyase were of end products. found only in the “natural” fermentation (Figures 8 and 9). No Origin of enzymes involved in other depolymerizing enzymes, such retting. The main enzymes found as cellulase or xylanase, nor other in this process were pectinase and hydrolases were found. Moreover, linamarase, and to a lesser extent, softening could be performed by amylase (data not shown). No inoculating commercial cellulase or xylanase activities were pectinesterase and depolymerizing found in retting. To elucidate the pectolytic enzymes on fresh and origin of cyanogen elimination and sterile cassava roots. the mechanism of root softening, two fermentations were carried out We suggest, therefore, that root simultaneously: one “natural,” used softening is a result of the combined as a control (CF), and one sterile action of both endogenous pectin (SF). pH and oxygen pressure of SF methyl esterase and exogenous were set on those of CF. Pectinase bacterial depolymerizing enzymes. and linamarase activities were But further studies are needed to assayed throughout the experiment. show the precise contribution of For SF, cassava roots were sterilized each pectic enzyme to root with HgCl2 and soaked in sterile softening. water.
1.0 123 123 15 123 123
123 123
0.8 123 123
123 123 123
1234
123 123 123 1234
123 12312314 23
1234 1234 10 123 123 123 1234 1234
0.6 123 123 123 123 123 1234 1234 1234
1234 1234 1234 123 123 123 123 123
1234 1234 123 1234
123 123 123 123 123 1234 1234 123 1234
1234123 1231423 12314 23 12312312314 23
1234 1234 1234 123 1234 per min/mg of proteins 123 123 123 123 123 - 0.4 1234 1234 1234 123 1234 123 123 123 123 123 5 1234 1234 1234 123 1234 1231423 1231423 12314 23 12312312314 23
1234 1234 1234 123 1234 123 123 123 123 123 1234 1234 1234 123 1234
1231423 1231423 12314 23 12312312314 23
1234 1234 1234 123 1234 0.2 123 123 123 123 123 1234 1234 1234 123 1234
123 123 123 123 123 1234 1234 1234 123 1234
Penetrometry index (mm/s) 1231423 1231423 12314 23 12312312314 23
1234 1234 1234 123 1234 0 mol of COO 123 123 123 123 123
1234 1234 1234 123 1234 µ 020406080 0 123 123 123 123 123 0 9.5 20 27 44 Time (hours) Time (hours)
Figure 6. Comparative evolution of softening Figure 7. Pectinesterase activity during retting. 12 123 between a sterile ( ) and a natural ( 123 = sterile fermentation;12 = control retting ( ). fermentation.)
205 Cassava Flour and Starch: Progress in Research and Development
50 Origin of cyanogen elimination. Of total cyanogenic compounds, 50%
1234567 1234567 were eliminated in SF and 97% in 40 1234567
1234567 1234567 CF (Figure 10). Enzyme assays 1234567
1234567
1234567
1234567 12345678 further confirmed endogenous 30 1234567 12345678 1234567 12345678
1234567 12345678 linamarase activity (Table 1).
1234567 12345678 1234567
1234567 12345678 1234567 1234567 12345678 1234567 Linamarase activity (measured as 1234567 12345678 1234567
1234567 12345678 1234567 20 1234567 12345678 1234567 β-glucosidase activity) in CF was 1234567 12345678 1234567 per min/mg of proteins
- 1234567 12345678 1234567 1234567 12345678 1234567 significant in fresh roots (specific 1234567 12345678 1234567
1234567 12345678 1234567
1234567 12345678 1234567
1234567 12345678 1234567 activity 9.4 units/mg protein). This 10 1234567 12345678 1234567 1234567 12345678 1234567
1234567 12345678 1234567 total activity then decreased after a
1234567 12345678 1234567
1234567 12345678 1234567 1234567 12345678 1234567 few hours. In SF, total activity
mol of COO 1234567 12345678 1234567
1234567 12345678 1234567 µ 0 remained constant, but at a low level. 0 9.5 20 27 44 The difference in β-glucosidase Time (hours) activity in the fresh roots between SF and CF may be attributed to the Figure 8. Pectate lyase activity during “natural” inhibitory effect of the HgCl used to fermentation. 2 sterilize the roots. However, as nearly 25% (Table 1) of the total β-glucosidase activity present in the sterile roots can degrade more than 0.3 50% of the total cyanide content of the fresh roots, we can assume that the level of linamarase activity
1234567
1234567 present in the intact roots was
1234567
0.2 1234567 1234567 sufficient to detoxify the roots. 1234567 1234567
1234567 1234567 1234567
1234567 1234567 1234567
1234567 1234567 1234567
1234567 1234567 1234567 1234567 1234567 1234567 Origin of the amylolytic activity. 1234567 1234567 1234567
1234567 1234567 1234567
1234567 1234567 1234567
min/mg of proteins 0.1 1234567 1234567 1234567 The amylase activity remained
1234567 1234567 1234567
1234567 1234567 1234567
1234567 1234567 1234567
mol of galacturonic acid per constant in SF, but disappeared after
1234567 1234567 1234567
µ 1234567 1234567 1234567 1234567
1234567 1234567 1234567 1234567 36 h of fermentation in CF (Figure 11). 1234567 1234567 1234567 1234567
1234567 1234567 1234567 1234567 1234567 1234567 1234567 1234567 Our data suggest that the amylase 0 0 9.5 20 27 44 activity detected in retting does not have a bacterial origin as suggested Time (hours) by different authors (Collard and Levi, Figure 9. Endopolygalacturonase activity during 1959; Oyewole and Odunfa, 1992; “natural” fermentation. Regez et al., 1987).
120
1234512345
12345 12345
100 12345 12345 12345 12345 12345
12345 12345 80 1234512345 1234512345
1234512345 12345
12345 12345 12345
12345 12345 12345 12345 60 12345 12345 12345
12345 12345 12345 12345
1234512345 1234512345 12345
1234512345 1234512345 123456 12345
40 1234512345 1234512345 12345 123456 12345 12345 12345 12345 123456 12345 12345 12345
12345 12345 12345 123456 12345 12345 12345 12345 12345 12345 123456 12345 12345 12345 12345 12345 12345 12345 123456 12345
12345 12345 12345 12345 20 12345 12345 12345 123456 12345 1234512345 1234512345 1234512345 12341523456 12345
1234512345 1234512345 1234512345 12341523456 12345 Percentage of total cyanide 1234512345 1234512345 1234512345 12345123456 1234512345
12345 12345 12345 123456 12345 0 12345 12345 12345 12345 12345 0 9.5 20 27 44 Time (hours)
12 123
12 123
Figure 10. Total cyanide evolution in control ( 12 ) and sterile ( 123 ) fermentations.
206 Cassava Lactic Fermentation in Central Africa:...
Table 1. β-glucosidase activities in control and communication) suggest that sterile fermentations. (Activities are Clostridium species (such as expressed in mmol per min/100 g of dry matter). Clostridium butyricum) could be involved with Bacillus species (such Time (h) Fermentation as Bacillus polymyxa) in root Control Sterile softening as pectinase producers. We did not see any involvement of 0 9.12 2.15 Geotrichum spp. or Corynebacterium 9.5 5.58 2.55 spp., as have other authors (Collard 20.0 6.10 1.75 and Levi, 1959; Okafor et al., 1984; 27.0 7.68 2.30 Regez et al.,1987). Yeasts (mostly 44.0 7.24 1.38 Candida species) were more involved in postretting.
Our biochemical analyses showed that retting is a fermentation in which 20,000 both endogenous and microbial enzymes coact to soften the roots and degrade cyanogenic, endogenous compounds. Our results suggested 10,000 that cell-wall degradation is initiated by endogenous pectinesterase, located in intercellular spaces and released
Total activity (U/L) by pH decrease. This is followed by microbial polygalacturonase and lyase 0 depolymerizing pectic chains. The 020406080 presence of pectic enzymes in cassava Time (hours) retting has previously been reported (Okafor et al., 1984; Oyewole and Figure 11. Amylase activity in control ( ) and sterile ( ) fermentations. Odunfa, 1992). But this work gives the first evidence of the vegetal origin of pectinesterase and of the in vivo activity of depolymerizing enzymes. Conclusions The amylase activity measured in These results suggest that retting is a retting seems to be of vegetal origin. complex heterolactic fermentation, But its low level of activity and with an interaction between lactic disappearance within the first 30 h of bacteria, Clostridium species, and retting suggest that it is not possibly Bacillus species. Heterolactic important to the retting process. bacteria (such as Leuconostoc mesenteroides) are the most Results of cyanide measurements important and numerous microflora indicate that endogenous linamarase in the process; they are responsible (measured as β-glucosidase activity) is for the physicochemical properties of the main enzyme responsible for retting (e.g., pO2 and pH) and the detoxification. We can assume, as production of the main organic acids Maduagwu (1983) suggested, that the (acetate and lactate). Clostridium level of linamarase activity present in species seem to be involved in intact roots is sufficient to detoxify butyrate formation, which is essential them of their cyanogen content for the organoleptic properties of the without help from any microbial final products. Moreover, recent linamarase. Nevertheless, if bacteria results (S. Kéléke, 1994, personal do not directly detoxify cassava roots,
207 Cassava Flour and Starch: Progress in Research and Development they could help degrade linamarin by Giraud, E.; Brauman, A.; Kéléke, S.; Lelong, destroying cell walls. B.; and Raimbault, M. 1991. Isolation and physiological study of an amylolitic strain of Lactobacillus Findings from our study have plantarum. Appl. Microbiol. helped other researchers: Biotechnol. 36:379-383.
(1) Isolate and characterize the first ______; Gosselin, L.; and Raimbault, M. amylolitic Lactobacillus plantarum 1992. Degradation of the cassava linamarin by lactic acid bacteria. (strain A6) (Giraud et al., 1991); Biotech. Lett. 14(7):593-598. (2) Improve fufu processing by significantly reducing retting time, Hosel, W. and Bartz, W. 1975. DF and increase the organoleptic glucosidases from Cicer arientum L. qualities of the final product Eur. J. Biochem. 57:607-616. (Ampe et al., 1994); Hungate, R. E. 1969. A roll tube method for (3) Adapt the process for areas with the cultivation of strict anaerobes. In: low water availability (Miambi et Norris, J. R. and Ribbons, D. W. al., n.d.). (eds.). Methods in microbiology, vol. 3B. Academic Press, NY.
McCready, M. H. 1918. Tables for rapid References interpretation of fermentation tube results. Can. J. Public Health 9:201. Ampe, F.; Brauman, A.; Trèche, S.; and Agossou, A. 1994. The fermentation Macy, J. M.; Snellen, J. E.; and Hungate, of cassava: optimization by the R. E. 1972. Use of syringe methods experimental research methodology. for anaerobiosis. Am. J. Clin. Nutr. J. Sci. Food Agric. 65:355-361. 25:1318-1323.
Bensadoun, A. and Weinstein, D. 1976. Maduagwu, E. N. 1983. Differential effects on Assay of protein in the presence of the cyanogenic glycoside content of interfering materials. Anal. Biochem. fermenting cassava root pulp by 70:241-250. β-glucosidase and microbial activities. Toxicol. Lett. (Amst.) Brauman, A.; Kéléke, S.; Mavoungou, O.; 15:335-339. Ampe, F.; and Miambi, E. n.d. Etude syntétique du rouissage traditionnel Miambi, E.; Machicout, M.; Trèche, S.; and des racines de manioc en Afrique Brauman, A. n.d. Le rouissage sans centrale (Congo). In: Agbor, E.; eau, une nouveau procédé de Brauman, A.; Griffon, D.; and Trèche, transformation des racines de S. (eds.). Cassava food processing. manioc. In: Agbor, E.; Brauman, A.; Institut français de recherche Griffon, D.; and Trèche, S. (eds.). scientifique pour le développement en Cassava food processing. Institut coopération (ORSTOM) Editorials, français de recherche scientifique Paris, France. (In press.) pour le développement en coopération (ORSTOM) Editorials, Paris, France. Collard, P. and Levi, S. 1959. A two-stage (In press.) fermentation of cassava. Nature (Lond.) 183:620-621. Okafor, N.; Ijioma, B.; and Oyolu, C. 1984. Studies on the microbiology of Cooke, R. D.; Blake, G. G.; and Battershill, cassava retting for fufu production. J. M. 1978. Purification of J. Appl. Bacteriol. 56:1-13. cassava linamarase. Phytochemistry (Oxf.) 17:381-383. Oladele Ogunsa, A. 1980. Changes in some chemical constituents during the de Man, J. C.; Rogosa, M.; and Sharpe, M. E. fermentation of cassava roots 1960. A medium for the cultivation of (Manihot esculenta Crantz). Food Lactobacilli. J. Appl. Bacteriol. Chem. 5:249. 23:130.
208 Cassava Lactic Fermentation in Central Africa:...
Oyewole, O. B. and Odunfa, S. A. 1992. ______and Massamba, J. n.d.a. La Extracellular enzyme activities consommation du manioc au Congo. during cassava fermentation for In: Agbor, E.; Brauman, A.; Griffon, “fufu” production. World J. Microbiol. D.; and Trèche, S. (eds.). Cassava & Biotechnol. 8:71-72. food processing. Institut français de recherche scientifique pour le Regez, P. F.; Ifebe, A.; and Mutinsumu, M. N. développement en coopération 1987. Microflora of traditional (ORSTOM) Editorials, Paris, France. cassava foods during processing and (In press.) storage: the cassava bread (chikwangue) of Zaire. Microb. ______and ______. n.d.b. Les modes Aliment. Nutr. 5:303-311. de transformation traditionnels du manioc au Congo. In: Agbor, E.; Somogyi, M. 1945. Determination of blood Brauman, A.; Griffon, D.; and Trèche, sugar. J. Biol. Chem. 160:61-68. S. (eds.). Cassava food processing. Institut français de recherche Starr, M. P.; Chatterjee, A. K.; Starr, P. B.; scientifique pour le développement en and Buchanan, G. E. 1977. coopération (ORSTOM) Editorials, Enzymatic degradation of Paris, France. (In press.) polygalacturonic acid by Yersinia and Klebsiella species in relation to Widdel, F. and Pfennig, N. 1984. clinical laboratory procedures. J. Dissimilatory sulfate- or Clin. Microbiol. 6:379-386. sulfur-reducing bacteria. In: Krieg, N. R. and Holt, J. G. (eds.). Bergey’s Trèche, S. n.d. Importance du manioc en manual of systematic bacteriology, alimentation humaine dans vol. 1. Williams and Wilkins, MD, differentes régions du monde. In: USA. p. 663-679. Agbor, E.; Brauman, A.; Griffon, D.; and Trèche, S. (eds.). Cassava food processing. Institut français de recherche scientifique pour le développement en coopération (ORSTOM) Editorials, Paris, France. (In press.)
209 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 24
A LACTIC ACID BACTERIUM WITH POTENTIAL APPLICATION IN CASSAVA FERMENTATION
E. Giraud*, A. Brauman**, S. Kéléke***, L. Gosselin*, and M. Raimbault†
Abstract Introduction
An amylolytic lactic acid bacterium, Lactic microflora play an important identified as Lactobacillus plantarum, role in the preparation of traditional was isolated from cassava roots foods based on fermented cassava, (Manihot esculenta var. Ngansa) during such as gari, chikwangue, fufu, and retting. Cultured on starch, the strain sour starch. But this microflora’s displayed a growth rate of 0.43 per function in preserving foods, hour, a biomass yield of 0.19 g/g, and eliminating cyanogenic compounds, a lactate yield of 0.81 g/g. The growth and improving organoleptic qualities is kinetics were similar on starch and not yet clear. Traditional technologies glucose. Enough enzyme was are still used to manufacture these synthesized, and starch hydrolysis foods. As fermentation occurs was not a limiting factor for growth. naturally with lactic microflora, the The synthesized amylolytic enzyme quality of the food products is not was purified by fractionated uniform. precipitation with ammonium sulfate and by anion exchange The mass inoculation of cassava chromatography. It was identified as roots with one or several selected an α-amylase with an optimal pH of strains would permit a better control 5.5 and an optimal temperature of over natural fermentation, thus 65 °C. The use of such a strain as a resulting in a product of improved cassava fermentation starter for gari quality. Because cassava contains production had the following effects: a mainly starch (more than 80% of dry change from a heterofermentative matter), the selection of a lactic acid pattern observed in natural bacterium capable of metabolizing fermentation to a homofermentation starch (i.e., amylolytic) is essential. one, a lower final pH, a faster pH decline rate, and a greater production But few lactic acid bacteria can of lactic acid (50 g/kg of dry matter). convert starch into lactic acid. Examples of amylolytic lactic acid bacteria are Streptococcus bovis, S. * Laboratoire de biotechnologie, Institut equinus, Lactobacillus amylophilus, L. français de recherche scientifique pour le développement en coopération (ORSTOM), amylovorus, L. acidophilus, L. Montpellier, France. cellobiosus, and others isolated from ** ORSTOM, Paris, France. animal digestive tracts and plant *** Laboratoire de microbiologie, Direction wastes (Champ et al., 1983; Cotta, générale de la recherche scientifique et technique (DGRST), Brazzaville, Congo. 1988; Nakaruma, 1981; Nakaruma † ORSTOM, stationed in Cali, Colombia. and Crowell, 1979; Sen and
210 A Lactic Acid Bacterium...
Chakrabarty, 1986; Sneath, 1986). (8) fermentation of different carbon Almost no information exists on the sources (API 50CH #5030 strips, physiology of these microorganisms. Biomérieux, France).
Below we describe how we isolated “Bergey’s Manual” (Sneath, 1986) and identified a new amylolytic lactic was used to evaluate results and acid bacterium from fermenting identify the different strains. cassava roots. We also investigated the physiology of this bacterium and the Strains and culture media properties of the amylase produced. Three strains were used as reference: Lactobacillus plantarum (Lacto Labo, Methods France), Streptococcus equinus CNCM 103233, and Lactobacillus Isolating and identifying strains amylophilus CNCM 102988T.
Peeled roots were immersed in rain JP2 medium (g/L). This water. Sampling was carried out consisted of: 4 days after fermentation by randomly selecting six roots cut into 0.5-cm M66 universal peptone 2.5 cubes and mixed under sterile Soya peptone obtained conditions. A sample of 60 g was by papain digestion 5 diluted in 540 ml of sterile peptone Casein peptone obtained solution. Then 0.1 ml of decimal by pancreatic digestion 2.5 dilutions were spread on JP2 medium (see below) in petri dishes. After Yeast extract 5 incubation for 48 h at 30 °C, the Meat extract 2.5 dishes were exposed to iodine vapor to MgSO4,7H2O 0.1 detect the starch hydrolysis areas. NaCl 3 Isolated strains were then purified by (NH ) SO 2 three successive transfers on JP2 4 2 4 K HPO 0.2 medium, and cultures routinely 2 4 checked for purity by microscopic Prolabo soluble starch 3 observation. Tween 80 (in ml) 0.4
Microorganisms were identified The pH was adjusted to 6.75 by: before sterilization.
(1) the configuration of the lactic Physiological studies were acid produced after treatment performed, using a de (Ivorec-Szylit and Szylit, 1965) Man-Rogosa-Sharpe (MRS) basal with the enzymes dehydrogenase medium (de Man et al., 1960) and l and d (Boerhinger Mannheim); changing the carbon sources to 5% (2) the microorganisms’ homolactic or glucose and 5% starch. heterolactic character, as determined by acetic acid or Culture conditions. Strains were (3) presence or absence of catalase; cultured in a 2-L bioreactor (4) microscopic and macroscopic (Biolafitte, France) at 30 °C and examination of morphology, agitated at 200 rpm. The pH was mobility, and spores; adjusted to 6.0 by adding NaOH (5 N). (5) Gram stain; Inoculation at 10% v/v was performed (6) arginine dissemination; with a 20-h pre-culture in the same (7) growth at 15 and 45 °C; and medium used for fermentation.
211 Cassava Flour and Starch: Progress in Research and Development
Analytical methods Bradford (1976) method, using a Biorad Kit (Cat No. 500-0001, The biomass concentration was Ivry-sur-Seine, France) and bovine determined by measuring the optical serum albumin as standard. density (OD) at 540 nm related to the dry weight measured after two Purification of amylase. washing and centrifugation cycles and Fermentation was stopped after drying at 105 °C for 24 h. For starch culture for 9 h. Cells were removed by cultures, hydrolysis of residual starch centrifugation (at 15,000 g for 15 min was performed with a mixture of at 4 °C), and the supernatant fluid amylases (thermamyl + dextrosyme, (750 ml) filtered through a cellulose supplied by Novo). The dry weight filter (0.45 µm pore size, HAWP type, and OD were then determined as Millipore, Saint Quentin les Yvelines, above. Lactic acid, glucose, acetic France) to remove cell debris. acid, and ethanol concentrations in the supernatant were assayed Powdered ammonium sulfate was by high-performance liquid then slowly added to the supernatant chromatography (HPLC). Compounds fluid under constant stirring at 4 °C. were separated by using an Aminex Most of the amylase activity was HPX 87H column (Bio Rad precipitated at between 50% and 70% Laboratory) with a 0.8 ml/min flow saturation.
(pump LDC 3200) of H2SO4 (0.012 N) solution at 65 °C. Analyses were After the ammonium sulfate carried out with a refractive index fractionation, the precipitated detector (Philips PU 4026). Total protein collected by centrifugation sugars in media containing starch (at 15,000 g for 30 min at 4 °C) was were also determined with anthrone, resuspended in 50 mmol/L KH2PO4/ using the Dubois et al. (1956) Na2HPO4 standard buffer (pH = 6.8). method. The enzyme solution was washed and concentrated with a PM-10 Amicon Amylase assay. The α-amylase ultrafiltration membrane. It was then activity was measured by incubating loaded onto a diethylaminoethyl 0.1 ml of appropriately diluted (DEAE) cellulose column (DE-52; enzyme solution with 0.8 ml of a Whatman Laboratory Sales, Hillsboro, solution containing 1.2% of Prolabo Oregon, USA). The column soluble starch in 0.1 mol/L (25 x 250 mm, flow rate 2.5 ml/min, citrate-phosphate buffer (pH = 5.5) at 25 °C) was previously equilibrated 55 °C. The reaction was stopped by with the standard buffer. The enzyme adding 0.1 ml of 1 mol/L H2SO4. After was eluted, using a concave, sodium incubation, residual starch contents chloride gradient (0-1.0 mol/L). were determined colorimetrically after Fractions (5 ml) were collected. The different periods at 620 nm by adding fractions that were enzymatically the 0.1 ml of the reaction mixture to most active were pooled, dialyzed 2.4 ml of an iodine solution overnight at 4 °C against the standard containing 30 g/L of KI and 3 g/L of I2 buffer, and used for further studies. and diluted to 4% with distilled water. They were kept at -30 °C. No activity was lost for at least 3 months under An enzyme unit is defined as the such conditions. amount of enzyme that permits the hydrolysis of 10 mg of starch in Polyacrylamide gel 30 min under the conditions electrophoresis. This was carried out described above. Protein according to Laemmli’s method (1970), concentration was estimated with the with a 10% running gel and 4%
212 A Lactic Acid Bacterium... stacking gel. Electrophoresis under physiological solution before cassava nondenaturating conditions was inoculation. performed in the absence of sodium dodecyl sulfate (SDS) and A container from each batch was β-mercaptoethanol in any buffer. Gels monitored every day to test the following were run at a constant 150 V for 1 h at parameters: 25 °C. Proteins were stained by the silver method (Oakley et al., 1980). (1) The pH was measured on a 10-g sample and homogenized in Amylase stain. After distilled water (20 ml). Moisture electrophoresis, gel was incubated was measured by drying a 10-g for 1 h at 30 °C in 0.1 mol/L sample at 105 °C for 24 h. citrate-phosphate buffer (pH = 5.5), (2) The number of lactic acid bacteria containing 1% of soluble starch. After (l.a.b.) was estimated on a 10-g two washes with distilled water, light sample homogenized in lanes (representing starch hydrolysis 90 ml of physiological sterile areas of amylase activity) were detected solution. Colonies were by immersing the gel in Lugol’s counted on MRS agar, using a solution. spread-plate technique on petri dishes and after incubation at Molecular mass determination. 30 °C and 48 h. SDS-PAGE electrophoresis was used to determine the approximate molecular mass of amylase. Marker proteins Results and Discussion (Biorad, Cat. No. 161-0315) used were myosin (200,000), β−galactosidase Isolation and identification of (116,250), phosphorylase-b (97,400), Lactobacillus plantarum A6 bovine serum albumin (67,000), and ovalbumin (45,000). Seven amylolytic microorganisms were isolated on JP2 medium from retted Assays on gari. Fresh imported cassava roots. Two were revealed cassava roots from Cameroon were by HPLC to have a capacity to obtained from Anarex (Paris, France). produce lactic acid from starch. Gari was prepared from peeled, washed Table 1 lists their morphological, cassava roots, which were chopped and physiological, and biochemical minced in a food mixer (SEB). The characteristics. The ability of these pulp obtained was packed tightly into cultures to use 49 different plastic, sterile, screw-capped carbohydrates was studied with containers (60 ml; OSI, A12.160.56) API 50CH #5030 strips. The results and placed at 30 °C. were compared, by computer, with the percentage of positive reactions of Three batches were prepared: different Lactobacillus species as per (1) natural fermentation, using the API. A 99.9% rate of similarity with endogenous microflora present; L. plantarum was observed and hence (2) fermentation after inoculation with identifying these cultures as strains of L. plantarum A6 (108 cfu/g of dried L. plantarum. The two strains, A6 and cassava), which had been cultured in A43, displayed precisely the same sugar bioreactors on cellobiose MRS medium; degradation profiles, which suggests (3) fermentation after inoculation with that they are probably the same. L. plantarum Lactolabo (108 cfu/g of dried cassava), which had been The amylolytic activities on JP2 cultured in bioreactors on MRS medium of L. plantarum A6, S. equinus, cellobiose. Cells were washed in and L. amylophilus indicated that the
213 Cassava Flour and Starch: Progress in Research and Development
Table 1. Characteristics of Lactobacillus plantarum strains A6, A43, and Lacto Labo (check).
Strain A6 A43 Check
Ratio of d:l lactic acid 69:31 66:34 73:27 Homolactic + + + Catalase - - - Bacterium shape Short rod Short rod Short rod Gram stain + + + Spore - - - Mobility - - - Dissemination of arginine - - - Growth at 15 °C + + + Growth at 45 °C - - -
starch hydrolysis zone was largest for almost identical. The strain therefore L. plantarum A6. It was therefore does not seem to require nutrients selected for further studies. other than those of the common strain, suggesting that mass Lactobacillus plantarum A6 growth production is possible. kinetics On starch MRS medium, the The growth of L. plantarum A6 on strain exhibits the same kinetic glucose MRS medium (Figure 1) is fully profiles (Figure 2) and the same yields comparable with that of L. plantarum as the standard strain. The rate of (Lacto Labo). The growth rate (0.43/h) starch hydrolysis was greater than the and biomass productivity (0.75 g/L per uptake rate, leading to a 3 g/L hour) were slightly lower than those of maltose peak during the seventh hour the standard (Lacto Labo) strain, but of fermentation (results not shown). the biomass and lactate yields were Thus, hydrolysis of starch is not a limiting factor.
Characterizing the amylolytic 50 25 enzyme
40 20 To characterize the amylolytic activity exhibited by L. plantarum A6, a comparison was made of the HPLC 30 15 profiles after starch hydrolysis by the cell-free extract and commercial 20 10 amylolytic enzymes (Aspergillus oryzae Biomass (g/L) α-amylase, Sigma A0273; potato
Glucose, lactate (g/L) β 10 5 -amylase, Sigma A7005, and Aspergillus niger amyloglucosidase, Sigma A3514). Under these 0 0 02468101214 conditions, the main products of Time (hours) starch hydrolysis analyzed by HPLC were glucose from amyloglucosidase, Figure 1. Fermentation of Lactobacillus maltose from β-amylase, and a plantarum A6 on MRS glucose mixture of glucose, maltose, and ( = glucose; = lactic acid; = biomass ). Temperature = 30 °C; oligosaccharide (retention time of pH = 6.0. 5.2 min) from α-amylase. The
214 A Lactic Acid Bacterium...
50 25 5
40 20 4
30 15 3
20 10 2 Biomass (g/L) Starch, lactate (g/L) Amylase activity (U/ml) 10 5 1
0 0 0 02468101214 Time (hours)
Figure 2. Fermentation of Lactobacillus plantarum A6 on starch MRS medium ( = starch ; = lactic acid; = biomass; = amylase activity). Temperature = 30 °C; pH = 6.0.
breakdown profile of starch by the purified fraction possessed an enzyme from L. plantarum A6 is amylase activity. These procedures similar to that of α-amylase, thereby were therefore considered sufficient indicating that the enzyme for purifying the extracellular synthesized by L. plantarum A6 is amylase activity of L. plantarum A6. extracellular α-amylase. The SDS-PAGE analysis of the purified fraction resulted in a Purification of amylase distribution between a clearly defined band (50 kDa) and a diffuse The results of purifying the amylase band with a molecular weight of produced by the strain L. plantarum close to 150 kDa. A6 are summarized in Table 2. The first step in purification was Hypotheses. Several hypotheses conventional (NH4)2SO4 fractionation. can explain these many amylase The 50%-70% fraction revealed forms. We find the most satisfactory maximum enzyme activity and was is that which suggests that the selected for further purification by purified extract consists of a DEAE-cellulose. The elution profile population of aggregates of a displayed only one amylase activity 50-kDa amylase. This interpretation peak. The purification procedure is based on the fact that most of the described above makes it possible, in bacterial amylases described have a only two stages, to obtain a protein molecular weight of this order fraction containing most of the (Fogarty, 1983). This type of amylase activity of L. plantarum A6 aggregation of purified enzyme was enriched by a factor of nearly 20. observed in Bacillus subtilis amylase (Robyt and Ackerman, 1973), with Testing the homogeneity of the zinc being the factor inducing fraction by electrophoresis under clumping. The clumping factor native conditions revealed a major remains to be defined in our case. protein and three others that were quantitatively unimportant. However, Further study is needed to all the proteins detected in the support this hypothesis. The
215 Cassava Flour and Starch: Progress in Research and Development
Table 2. Purification of α-amylase of Lactobacillus plantarum strain A6 cultivated in a modified MRS
medium containing 2% (w/v) soluble starch and 0.5 g/L CaCl2 at 30 °C.
Materials Volume Protein Activity Specific activity Yield Purification (ml) (mg) (U) (U/mg) (%) (fold)
Culture filtrate 750.0 82.5 35100 425 100.0 1.0
(NH4)2SO4 (50%-70% fraction) 39.0 18.1 25935 1433 73.9 3.4
Ultrafiltrate 8.8 10.4 16016 1540 45.6 3.6
DEAE-cellulose (117-130 fractions) 61.8 1.5 12484 8270 35.6 19.5
amount of enzyme isolated was not amylase from L. plantarum A6 are very large enough for further investigation. similar to those of Bacillus subtilis Immunological characterization would (Fischer and Stein, 1960; Fogarty, probably determine the type of relation 1983; Robyt and Ackerman, 1973; between the different amylase forms and Welker and Campbell, 1967): observed and thus confirm the extracellular enzyme, identical hypothesis. optimal pH (5.5), identical optimal temperature (65 °C), presence of Effects of pH and temperature tyrosyl phenolic groups at the active on amylase activity. The effect of pH site, and presence of multiple forms on enzyme activity was studied in a (aggregates). 3.0 to 7.5 pH range with 0.1 mol/L citrate-phosphate buffer at 55 °C. The We speculated that the enzymatic activity profile according to exceptional capacity of L. plantarum temperature was determined within a A6 to break down starch might have 10 to 80 °C temperature range under standard conditions (see above). The optimal pH was 5.5 and the optimal temperature was 65 °C (Figures 3 100 and 4).
Compared with the characteristics 80 of the lactic acid bacterial amylases described in the literature, the properties of the enzyme synthesized 60 by L. plantarum A6 are different. The enzyme from a Leuconostoc spp. studied by Lindgren and Refai (1984) 40
had a pH optimum of 6.0 and a Relative activity (%) temperature optimum of 40 °C. Two active enzyme fractions were clearly 20 separable by isoelectric focusing. The enzyme isolated from L. cellobiosus (Sen and Chakrabarty, 1986) had a 0 molecular weight of 22.5 to 24 kDa, a 345678 pH optimum from 6.3 to 7.9, and a pH temperature optimum of 40 to 50 °C. Figure 3. Effects of pH on amylase activity at But the characteristics of the 55 °C.
216 A Lactic Acid Bacterium...
100 A
90
80
5 70 B 4 60 3
50 Inactivity (%) 2 2.8 3.0 3.2 3.4 3.6 40 Relative activity (%) 1,000/T (K-1)
30
20
10
0 0 20 40 60 80 100 120 Temperature (°C)
Figure 4. Effects of temperature on amylase activity at pH = 5.5. (A) Relative activity versus temperature; (B) Arrhenius plot. been a result of transfer of genetic fermented cassava showed a steep fall material between Bacillus subtilis and from 6.2 to 4.3 (assay 1), and both L. plantarum, which could be possible, inoculation assays (2 and 3) from because both are microorganisms 6.2 to 3.9. This pH shift was found in the natural microflora of correlated with lactic acid production, fermented cassava (Nwanko et al., which was the principal metabolite 1989), and whose amylase activities produced (Figure 6). These data are very similar. Further investigation confirm that the lactic acid bacteria would answer this question. are the predominant fermentative microflora. In all three assays, this Inoculation effect of Lactobacillus flora reached 5.109 cfu/g after 24 h of plantarum A6 on cassava fermentation (Figure 5). fermentation In the natural cassava Three different assays were carried fermentation, within the first 24 h, a out: (1) natural cassava fermentation, simultaneous production of lactic and (2) cassava inoculated with L. acetic acids and traces of propionic plantarum A6, and (3) cassava and butyric acids and ethanol were inoculated with a control strain, L. observed. But, although the acetate plantarum Lacto Labo. content reached its maximum level (10 g/kg DM) and remained constant Evolution of pH, organic acids, after the first day of fermentation, the and lactic acid bacteria. In all lactate concentration began three assays, a rapid pH decrease was increasing from the second day of the observed from the start of process. This suggests that fermentation (Figure 5). The naturally fermentation is primarily related to
217 Cassava Flour and Starch: Progress in Research and Development
7 10.0 an heterolactic flora growth, which is supplanted by a more acid-tolerant 9.5 homolactic flora. 6 9.0 This hypothesis is supported by Oyewole and Odunfa (1990), who studied the characteristics and 5 8.5 pH distribution of lactic acid microflora during the preparation of fufu. They 8.0 reported a predominant development Leuconostoc mesenteroides 4 of , which
Log 10 lactic acid bacteria/g was subsequently replaced by 7.5 L. plantarum. They suggested that this sequence resulted because 3 7.0 L. mesenteroides was unable to 0 20406080100 tolerate increasing acidity. Time (hours)
Figure 5. Changes in pH and numbers of In the inoculated fermentations, lactic acid bacteria (l.a.b.) during the lactic acid content was higher. cassava fermentation. ( = pH and The production kinetics of this acid = l.a.b. in natural fermentation; = pH and = l.a.b. in fermentation were identical in both L. plantarum inoculated with Lactobacillus strains during the first 24 h. But, on plantarum A6; = pH and = l.a.b. the second day, this concentration in fermentation inoculated with L. reached its maximum (40 g/kg DM) plantarum Lacto Labo.) and remained constant in the control strain. In contrast, in the amylolytic 6 strain (L. plantarum A6), lactate production continued to rise, increasing by 25%. 5 Traces of ethanol, propionate, and butyrate were also found in the 4 inoculated fermentation assays. Furthermore, the lower acetate production showed that a massive 3 inoculation with an L. plantarum strain inhibited the development of the 2 natural heterolactic microflora.
1
Concentration (g/100 g of dry matter) Conclusions
The presence of amylase in lactic acid 0 0 20 40 60 80 100 bacteria has already been reported. Time (hours) But, as far as we know, no author has described any amylolytic strain of L. Figure 6. Evolution of lactate and acetate plantarum. When investigating the concentration during cassava bacterial microflora of fermented fermentation. ( = lactate and = acetate in natural fermentation; cassava roots, Regez et al. (1988) ' .'= lactate and = acetate in isolated numerous L. plantarum fermentation inoculated with strains, but did not report any Lactobacillus plantarum A6; = lactate and = acetate in fermentation amylolytic strains. Scheirlinck et al. inoculated with L. plantarum Lacto Labo.) (1989) studied the integration of the
218 A Lactic Acid Bacterium...
α-amylase gene of Bacillus Fischer, E. H. and Stein, E. A. 1960. stearothermophilus in the genome of an α-Amylases. In: Boyer, P. D.; Lardy, L. plantarum strain, but did not verify H.; and Myrbäck, K. (eds.). The enzymes, vol. 4. Academic Press, NY. the expression, stability, and p. 313-343. competitiveness of the transformed strain in a natural medium. Fogarty, W. M. 1983. Microbial enzymes and biotechnology. Applied Science In our research, we had isolated Publishers, Barking, Essex, UK. a natural amylolytic strain of L. Ivorec-Szylit, O. and Szylit, M. 1965. plantarum from cassava roots. Our Contribution à l’étude de la data, as reported here, suggest that dégradation des glucides dans le this new lactic acid bacterium is of jabot du coq: mise en évidence et particular interest, not only for its dosage des stéréo-isomères d et l lactates. Ann. Biol. Anim. Biochim. taxonomy, but also for its capacity to Biophys. 5:353-360. develop rapidly and massively in starch-based media. Laemmli, U. K. 1970. Cleavage of structural proteins during the assembly of Finally, preliminary trials of the head of bacteriophage T4. Nature (Lond.) 227:680-685. inoculating cassava with L. plantarum A6 for gari production demonstrate Lindgren, S. and Refai, O. 1984. Amylolytic that this strain may play a significant lactic acid bacteria in fish silage. role in developing organoleptic J. Appl. Bacteriol. 57:221-228. qualities, and in standardizing and Nakaruma, L. K. 1981. Lactobacillus preserving the final product because of amylovorus, a new starch-hydrolyzing the large amounts of lactic acid species from cattle waste-corn produced and the resulting faster and fermentations. Int. J. Syst. Bacteriol. significant drop in pH values. 31:56-63.
______and Crowell, C. D. 1979. Lactobacillus amylophilus, a new References starch-hydrolyzing species from swine waste-corn fermentation. Dev. Bradford, M. M. 1976. A rapid and sensitive Ind. Microbiol. 20:531-540. method for the quantitation of microgram quantities of protein, Nwanko, D.; Anadu, E.; and Usoro, R. 1989. utilizing the principle of protein dye Cassava-fermenting organisms. binding. Anal. Biochem. 72:248-254. MIRCEN J. Appl. Microbiol. Biotechnol. 5:169-179. Champ, M.; Szylit, O.; Raibaud, P.; and Ait-Abdelkader, N. 1983. Amylase Oakley, B. R.; Kirsh, D. R.; and Morris, N. R. production by three Lactobacillus 1980. A simplified ultrasensitive strains isolated from chicken crop. silver stain for detecting proteins in J. Appl. Bacteriol. 55:487-493. polyacrylamide gels. Anal. Biochem. 105:361-363. Cotta, M. A. 1988. Amylolytic activity of selected species of ruminal bacteria. Appl. Environ. Microbiol. Oyewole, O. B. and Odunfa, S. A. 1990. 54:772-776. Characterization and distribution of lactic acid bacteria in cassava de Man, J. C.; Rogosa, M.; and Sharpe, M. E. fermentation during fufu production. 1960. A medium for the cultivation of J. Appl. Bacteriol. 68:145-152. lactobacilli. J. Appl. Bacteriol. 23:130-135. Regez, P. F.; Zorzi, N.; Ngoy, K.; and Balimandawa, M. 1988. Evaluation Dubois, M.; Gilles, K. A.; Hamilton, J. K.; de l’importance de quelques souches Rebers, P. A.; and Smith, F. 1956. de Lactobacillus sp. pour Colorimetric method for determination l’acidification de differents aliments à of sugars and related substances. Anal. base de manioc. Lebensm. Chem. 28:350-356. 21:288-293.
219 Cassava Flour and Starch: Progress in Research and Development
Robyt, J. F. and Ackerman, R. J. 1973. Sneath, P. H. A. (ed.). 1986. Bergey’s manual Structure and function of amylase. of systematic bacteriology, vol. 2. II. Multiple forms of Bacillus subtilis Williams and Wilkins, Baltimore, MD, α-amylase. Arch. Biochem. Biophys. USA. 155:445-451. Welker, N. E. and Campbell, L. L. 1967. Scheirlinck, T.; Mahillon, J.; Joos, H.; Dhaese, Comparison of the α-amylase of P.; and Michiels, F. 1989. Integration Bacillus subtilis and Bacillus and expression of α-amylase and amyloliquefaciens. J. Bacteriol. endoglucanase genes in the 94:1131-1135. Lactobacillus plantarum chromosome. Appl. Environ. Microbiol. 55:2130-2137.
Sen, S. and Chakrabarty, S. L. 1986. Amylase from Lactobacillus cellobiosus D-39 isolated from vegetable wastes: purification and characterization. J. Appl. Bacteriol. 60:419-423.
220 Cassava Wastes:...
CHAPTER 25
CASSAVA WASTES: THEIR CHARACTERIZATION, AND USES AND TREATMENT IN BRAZIL1
M. P. Cereda* and M. Takahashi**
Introduction cluster in certain areas or cities. For example, sour or fermented-starch Cassava is widely grown in Brazil. It factories are concentrated by the is used fresh, that is, directly, in hundreds in two districts of Minas cooking; processed into a typical Gerais State: Divinópolis and Pouso flour, known as farinha; and for Alegre. Paranaví, a district of Paraná starch extraction. All the resulting State, has a concentration of about food products have no or nontoxic 150 flour factories of different sizes. levels of cyanide (Table 1). Most cyanide is carried away by the wastes, whether liquid or solid. Cassava Structure and Composition The crop is grown in diverse production systems, ranging from The literature on cassava’s structure small farms to plantations. and chemical composition is variable. Depending on their quantity and Nevertheless, the data overall suggest composition, cassava residues can that the cassava root is caloric, and damage the environment and even generates about 1,500 cal/kg from constitute profit losses. Culinary use, about 350 g/kg of carbohydrates. for example, does not produce The average values of other significant amounts of residues. In components are about 50 g/kg. contrast, industrial use may cause Phosphorus and calcium contents are environmental problems. Even tiny higher. Iron may occur, but in low factories such as the casas de farinha quantities. Hegarty and Wadsworth can produce significant quantities of (1968) state that raw cassava usually residues, because of their tendency to has an iron content of 1 to 2 mg/100 g of dry matter, but warn that if the analytical equipment used is made of iron, then such content may reach as high as 3.2 mg/100 g. * Faculdade de Ciências Agronômicas (FCA), Universidade Estadual Paulista (UNESP), São Table 2 shows the differences in Paulo, Brazil. composition when cassava leaves are ** Instituto Agronômico do Paraná (IAPAR), considered. Oke (1968) details Paraná State, Brazil. cassava root composition, mainly as 1. No abstract was provided by the authors. mineral contents, as follows:
221 Cassava Flour and Starch: Progress in Research and Development
Humidity: 71.50% The literature differs on the Dry matter (g/100 g): nitrogen fraction of cassava roots. The crude protein = 2.60 traditional methodology evaluates crude fiber = 0.43 ash = 2.40 proteins by multiplying crude nitrogen lipids = 0.46 by a factor. Cereal or other, vegetable, carbohydrates = 94.10 factors are calculated in this way. Oke Ash minerals (g/kg): (1968) does not consider this accurate nitrogen = 0.84 enough because a factor for cassava potassium = 1.38 phosphorus = 0.15 amino acids has yet to be established. calcium = 0.13 Despite being low, cassava proteins Other minerals (mg/kg): are overestimated because root sodium = 56.00 nitrogen fractions include both a iron = 18.00 proteinic fraction and nonproteinic boron = 3.30 molybdenum = 0.90 compounds. The nitrogen of the magnesium = 12.00 linamarin radical (CN), for example, copper = 8.40 could be wrongly considered as part of zinc = 24.00 the protein evaluation of raw cassava aluminum = 19.00 or cassava fractions. Other components: oxalate = 0.32% phytic acid = 76.00% Sreeramamurthy (1945) reports HCN = 38.00 mg/100 g that the traditional solvents of protein methodology fail to extract some nitrogen, part of which is of a proteinic The potassium content is greater nature. For example, copper than that of calcium, phosphorus, hydroxide separates and precipitates and iron. The idea that cultivating only 10% of total protein. The cassava cassava weakens the soil is probably proteinic fraction contains arginine, based on this fact. tryptophan, and cystine, and important amino acids. Cassava root Group B vitamins occur in protein is small in quantity rather cassava varieties with yellow pulp. than low in quality when compared These varieties are normally used by with casein, egg albumin, and the factories only in the northern states of protein fractions of cabbage and Brazil. Cassava roots have high sweetpotatoes. In contrast, Rogers vitamin C content, but it can be (1965) suggests that cassava protein is destroyed in factory processing or low in histidine, proline, glycine, and cooking. amino acids containing sulfur (e.g.,
Table 1. Composition (in percentage) of some typical cassava products, Brazil. Numbers are rounded.
Component Product
Farinha Starch Sour Chips flour starch
Humidity 1.2 1.1 1.6 0.9 Dry matter: Carbohydrates 93.0 97.3 95.6 94.0 Proteins 1.3 0.6 1.5 1.7 Lipids 0.1 0.3 0.3 0.3 Crude fiber 3.3 0.6 0.7 1.1 Ash 1.1 0.1 0.3 0.4 Cyanide 0.0 0.0 0.0 1.6
SOURCE: Faculdade de Ciências Agronômicas (FCA), Universidade Estadual Paulista (UNESP), unpublished data.
222 Cassava Wastes:...
Table 2. Central American cassava cultivars: root and leaf composition. Numbers are rounded.
Component Root size Leaves
Long, thin Medium Short, thick
Humidity (%) 62.10 61.10 62.10 77.20 Dry matter (g/100 g): Fiber 1.60 1.25 1.14 2.54 Lipids 0.65 0.20 0.24 1.31 Nitrogen 0.32 0.17 0.11 1.10 Carbohydrates 32.95 34.18 34.70 10.33 Ash 1.20 1.20 0.86 1.77 Other components (mg/kg): Calcium 46.00 27.00 27.00 206.00 Phosphorus 78.00 66.00 43.00 95.00 Iron 1.60 0.50 0.50 3.50 Carotene 0.01 0.01 0.01 4.53 Thiamine 0.09 0.06 0.05 0.15 Riboflavin 0.04 0.04 0.30 0.30 Niacin 0.82 0.72 0.60 2.02 Ascorbic acid 32.00 40.75 41.40 211.00
SOURCE: Calculated from Martelli, 1951.
methionine, cystine, threonine, of which 1.79% is composed of isoleucine, and tryptophan). reducing sugars (0.93% glucose, 0.43% fructose, and 0.43% maltose) Cassava juice is milky, smells of and 1.71% nonreducing sugars cyanide, and consists of 91.00% (1.70% saccharose and 0.01% water, 0.13% essential oils containing raffinose). Oke considers starch sulfur, 2.30% gum, 1.14% saponins, content as being 35% of the fresh 1.66% glycosides, and 3.80% matter, and possibly higher if total nonspecified components. carbohydrates are calculated by difference. Amylase hydrolyzes Oke (1968) reported cassava lipids cassava starch to 48% in its granular from 0.1% to 1.0%, made up of 35% or raw form and to 78% when palmitic, 3% stearic, 39% oleic, 18% previously boiled. linoleic, and 5% linolenic acids. Sugar originating from starch may The literature rarely mentions increase if fermentation takes place. cassava fiber. Despite cassava roots According to Amido (Um novo being fibrous, the processing method caminho..., 1973), fermentation that uses acid and alkaline during starch extraction and hydrolysis yields only about 2.0% purification causes loss of starch fiber, whereas other methods (such as because it turns into soluble sugars. neutral detergent analysis or enzymatic analysis) yield almost 20%. Sreeramamurthy (1945) concluded that cassava roots are mainly starchy. Carbohydrate is the highest They contain less than 1% protein, fraction of cassava root composition, have a very low lipid content, and are with starch constituting the largest poor in minerals and group B part. Oke (1968) puts the nonstarchy vitamins, although fresh roots have fraction of the carbohydrates at 3.5%, considerable vitamin C content.
223 Cassava Flour and Starch: Progress in Research and Development
Toxic Cassava Glycosides oxidative phosphorylation pathway, combining with cytochrome-oxidase Cooke (1979) describes both to inhibit electronic transportation lotaustralin and linamarin, the toxic and thus the formation of adenosine glycosides found in the cassava plant triphosphate (ATP). (Table 3), as being able to generate hydrocyanic acid. Although free For animals, calculating the cyanide is well known to be toxic, the quantity sufficient to cause death toxicity of glycocyanide is still (lethal dose) is done by experiment unknown. and expressed in mg per kilo of live weight. Oke (1969) mentions that Oke (1969) reported that 1 mg/kg of live weight is considered linamarin is a β-glucoside of acetone the limit for humans, and is used to cyanohydrin, and lotaustralin of classify cassava roots into poisonous ethyl-methyl-ketone-cyanohydrin. or nonpoisonous, according to the The more representative glucoside is amount of cyanogenic potential in the linamarin, which constitutes 80% of root. The literature mentions values total glucosides. He also suggested ranging from 15 to 400 mg of that glucosides in linked form are not hydrocyanic acid per kg of fresh toxic to the plants themselves. cassava roots, although average values are 30 to 150 ppm (Carvalho Oke hypothesized that the and Carvalho, 1979). glucosides are intermediate compounds in protein synthesis, such Oke (1969) suggests that, in as from amino acids that are processed foods made from cassava, constituted from the nitrate absorbed the hydrolytic enzyme of the plant by roots. Thus, the cyanogenic linamarase remains active and glucosides are stable intermediates catalyzes a reaction that releases that do not accumulate if conditions molecules of glucose, acetone, and for protein synthesis are favorable. hydrocyanic acid in proportions of Glucoside synthesis probably starts 1:1:1. Linamarase has an optimal pH with glycine. of 5.5 to 6.0. Glucose can act as an antidote because it changes the The toxic action of cyanide reaction’s direction and cooperates (released when cell walls are with glucoside synthesis. damaged) on animals is explained by the cyanide’s affinity to iron, Microorganisms consume free combining with hemoglobin to form glucose in preference to glucoside. cyanohemoglobin. In higher plants Coop and Blakey (1948), cited by Oke and microorganisms (Cereda et al., (1969), confirmed this hypothesis. 1981), cyanide interferes with the When an extract of cassava in a solution containing 1 to 3 ppm of HCl with a pH of 6.5, was placed in the Table 3. Cyanogen glycoside concentration presence of 2% glucose, the released (mg/kg of tissue) in cassava tissues of cyanide content did not change. Nor sweet and bitter cultivars (Manihot was the extract toxic when incubated esculenta Crantz). with rumen liquid. Determining the Cultivars Seeds 10-day-old Mature Roots pH is important, because reaction plantlets leaves rate depends on it. Animals, in general, have a detoxification Sweet 0 285.0 468.0 125.0 mechanism that can prevent death Bitter 7.5 245.0 310.0 185.0 when reaction is slow. It operates in SOURCE: Nartey, 1981. swine, whose stomachs are
224 Cassava Wastes:... monogastric, with a pH of 3.0, but flour making by pressing bulk does not effectively prevent death in quantities of cassava roots. It is also bovines, which have polygastric formed during starch extraction, but stomachs, with a pH of 7.0. the water used in the process dilutes the manipueira, reducing its organic Microorganisms can develop on load and cyanide content, but vastly substrates that contain cyanide if increasing its output. Water from they have an anaerobic metabolism— washing roots is also considered as an alternative mechanism to the liquid waste. Figures 1 to 5 show the respiratory chain (Cereda et al., relationships between cassava 1981)—or if they can detoxify cyanide by splitting the radical into carbon and nitrogen (Jensen and 891 Abdel-Ghaffar, 1969). This fact may explain the related fertilizing effect of 193 waste-water spillage from cassava processing.
65 Cassava Wastes
Cassava wastes are plant residues 75 generated by processing. Waste quality and quantity vary greatly 127 because of such factors as plant age, time after harvesting, kind of 51 152 industrial equipment, and its adjustment. Water waste Roots
In Brazil, cassava roots are mostly Sieved mass Chips processed into flour (which generates Pressed mass Leaves more solid residues) and starch (more liquid residues). Some solid wastes Ground mass are brown peel, inner peel, unusable roots, crude bran, bran, bagasse, and Figure 1. Cyanide content (ppm of HCN) of plant parts, products, and wastes of flour refuse. Among the liquid wastes processing cassava cultivar is manipueira, which is formed during IAC 12 829.
200 250
123456 123456
123456 123456 160 123456 200 123456 123456 123456
123456 123456 123456
123456 123456 123456 120 123456 150 123456 123456 123456 123456 123456
123456 123456 123456
123456 1234567 123456 123456 80 123456 1234567 100 123456 123456 123456 1234567 123456 123456 1234567 123456 Free cyanide
123456 1234567 123456 123456 1234567 123456 Total cyanide
123456 1234567 123456 123456 1234567 123456 40 123456 1234567 123456 50 123456 1234567 123456 123456 1234567 123456 123456 1234567 123456
123456 1234567 123456 123456 1234567 123456
123456 1234567 123456 123456 1234567 123456 0 123456 1234567 123456 0 123456 1234567 123456 Waste Ground Roots Waste Ground Roots water mass water mass
Figure 2. Free and total cyanogens (ppm of HCN) in products of a cassava flour factory (Equipamento Zaccharias), using cassava cultivar IAC 12 829 at 24 months old, São Paulo, Brazil.
225 Cassava Flour and Starch: Progress in Research and Development
Peelings Roots Discards 196 kg 1,000 kg 90 kg 47% m.c. 52% m.c. 57% m.c.
Ground mass 714 kg 58% m.c.
Waste water (manipueira) Pressed mass 289 kg, 90% m.c. 425 kg Total cyanide = 120 ppm 36% m.c.
Crueira Evaporated Oven-drying (type of solid waste) water 40 kg, 48% m.c. 133 kg
Flour (farinha) 253 kg 0.74% m.c.
Figure 3. Mass balance of a fermented-starch factory, Colombia. (m.c. = moisture content.) (After Arguedas and Cooke, 1982.)
Peelings Roots Discards 68 kg 1,000 kg 3 kg 68% m.c. 52% m.c. 55% m.c.
Waste water (diluted manipueira) 10,620 L Bran Grinder + water 95% m.c. 1,120 kg Sieve + water Total cyanide = 60 ppm 85% m.c. 5,000 biological oxygen demand
Wet starch 149 kg 52% m.c.
Figure 4. Mass balance of a fermented-starch factory, which used cassava variety Branca de Santa Catarina at 24 months old, Minas Gerais State, Brazil. (m.c. = moisture content.)
226 Cassava Wastes:...
Drying floors 3.5
123
123
3.0 123
123
123 2.5 123 123
123
123 123
123
123 2.0 1231234
123123 1213231234
123123 1231234 1234 123
121323 1213234 1234123
123 123 12 1.5 121323 1231234 1234 1234123 123 121323 1213231234 1234 121231423
121323 1231234 1234 1231423 123 123 12 121323 1213234 1234 1231423
123 123 121323 1213231234 1234 121231423
123 121323 1231234 1234 1231423 1.0 123 123 12 1234123 121323 1231234 1234 1231423
123 123 12 1231423 121323 1213234 1234 1231423
1213234123 121323 1213231234 1231234123 121231423
1234123 121323 1231234 1234123 1231423 123 123 123 12 0.5 1234123 121323 1231234 1234123 1231423
123 123 123 123 12 1234123 121323 1231234 1234123 1231423
1213234123 123121323 1213231234 1213234123 121231423
1234123 121323 1231234 1234123 1231423 123 123 123 123 12 0 1234123 123123 1231234 1234123 1234123 Mibo Grounted Foster Hand cut Average
Covered trays 5.0
1234 Cyanide (ppm)
1234
1234
1234
1234 4.0 1234 1234 1234 1234
1234
1234 1234
1234 1234
1234 1234 1234
3.0 1234 1234 1234
1234 1234 1234
1234 1234 12345
1234 123 1234 1234 12345
1234 1234 1234 1234 123 12345
1234 1234 12345 1234 1234 123
1234 1234 12345
1234 1234 123 2.0 1234 1234 12345
1234 1234 1234 1234 123 12345
123451234 12341234 12345 1234 1234 123 123451234 12345 12341234 123412345
1231423451234 123412345 123412341234 123123412345
123451234 12345 12341234 123412345 1234 1234 1234 123 1.0 123451234 123451234 12341234 123412345 1234 1234 1234 123 123451234 123451234 12341234 123412345
1231423451234 1231423451234 123412341234 123123412345
123451234 123451234 12341234 123412345 1234 1234 1234 123
123451234 123451234 12341234 123412345
1234 1234 1234 123 123451234 123451234 12341234 123412345 0 Mibo Grounted Foster Average
Figure 5. Cyanide123 reduction in cassava chips processed at three factories and by hand cutting, Brazil.
123 1234
123 ( = 5 kg/m2 123 = 10 kg/m2 1234 = 15 kg/m2 = Average.) 123 1234
processing, cultivars, and wastes in factories, if the inner peel is highly the material balance of cassava flour fibrous, it is best taken off. In and sour starch production. industrial terms, peelings are residues and refer to the mixture of Solid wastes both inner peel and bark. Table 4 shows the average composition of Peelings. The brown peel, several samples of peelings. Peelings sometimes called bark, of cassava can be used as fertilizer or animal roots corresponds, in technical terms, feed. to the periderm and varies between 2% and 5% of the root total. It is thin Discards. These are produced and cellulosic, and although usually during selection, so as not to dark brown, can be white or overwork the rasper. Their cream-colored. A small quantity of composition is similar to that of inner peel, or cortical parenchyma, cassava roots but is more fibrous may come off with the bark, causing because they contain the peduncle. losses in starch factories. In farinha Moisture content is 55%-60%. The
227 Cassava Flour and Starch: Progress in Research and Development
Table 4. Chemical composition of cassava peelings. Average values of several samples are given. Dashes indicate that no data were available.
Component Peelings
Outer (bark) Inner Mixture
Humidity (%) 48.3 65.6 72.3 Dry matter: Volatile solids (%) - - 26.2 Ash (%) 4.0 3.0 1.4 Soluble carbohydrates (%) - - 7.9 Starch (%) 0 58.0 32.0 Lipids (%) 3.0 2.0 0.6 Nitrogen (%) 0.6 1.3 2.1 Fiber (%) 41.0 6.0 - Lignin (% SV) - - 6.5 Free cyanide (ppm) - - 23.9 Total cyanide (ppm) 0 320.0 120.0 Phosphorus (ppm) 60.0 - 60.0 Potassium (ppm) 430.0 - 430.0 Calcium (ppm) 280.0 - 280.0 Magnesium (ppm) 80.0 - 80.0 Iron (ppm) 5,538.0 - 26.0 Copper (ppm) 9.0 - 9.0 Zinc (ppm) 21.0 - 21.0 Manganese (ppm) 104.0 - 103.0 Sulfur (ppm) 110.0 - 320.0 Boron (ppm) 18.0 - 18.0 Volatile acidity (mg acetic acid/L) - - 5,548.0 Alkalinity (mg bicarbonate/L) - - 2,191.0 C/N ratio - - 6.4 C/P ratio - - 0.3
SOURCE: Motta, 1985. quality of discards depends on the the composition of sun-dried bran cultivar and on root age. Together from fermented-starch factories in with bran, discards may be used raw Minas Gerais, Brazil. as animal feed, thus bringing extra income for the industry. The values Crude bran. Another type of shown in Figures 3 and 4 may be solid waste is crude bran (farinhão or overestimated, because the process is crueira), which is made up of pieces of still being investigated. root and inner peel. In cassava-flour processing (at Equipamento Bran or bagasse. This solid Zaccharias, São Paulo State), these waste is made up of fibrous root are separated out by sieving before material, and contains starch that being oven-dried. Table 7 (p. 231) physically could not be extracted. It shows the composition of such waste. is produced as starch is separated. It At other factories (e.g., Mádia, Paraná has a large absorption capacity and State), these residues are replaced by may contain about 75% moisture. fine threads (fiapos) made up of Table 5 shows the chemical cassava fibers. Another solid residue composition of bran after partial is cassava-flour refuse, the grated drying, with differences according to mass that daily falls and collects on the technology used. Table 6 shows the floor.
228 Cassava Wastes:...
Table 5. Differences in chemical composition of bran according to technology adopted. Dashes indicate that no data were available.
Componenta Type of technology
Royalb Minasc Fiaposb
Humidity (%) 9.42 14.82 9.52 Dry matter: Ash (%) 0.83 3.77 0.66 Soluble carbohydrates (%) 0.01 - - Starch (%) 69.76 74.99 63.85 Lipids (%) 0.65 0.28 0.83 Nitrogen (%) 0.24 1.86 0.32 Fiber (%) 11.08 7.81 14.88 Total cyanide (ppm) 0 0 - Phosphorus (ppm) - 30.00 - Potassium (ppm) - 280.00 - Calcium (ppm) - 90.00 - pH 4.00 - - a. No data were available for the following components: volatile solids, lignin, free cyanide, magnesium, iron, copper, zinc, manganese, sulfur, boron, volatile acidity, alkalinity, C/N and C/P ratios, chemical oxygen demand, or titratable acid. b. Large factory. c. Small, traditional factory.
Table 6. Average composition of sun-dried bran these are sun-dried and used as from 20 fermented-starch factories fertilizer. The use of thin starch is (traditional) from Pouso Alegre and Divinópolis, Minais Gerais, Brazil. also uncommon.
Component Average values (%)a Manipueira. Diluted Pouso Alegre Divinópolis manipueira is a liquid waste from cassava starch extraction and Starch 63.6 2.78 sour-starch manufacture. It may be b Soluble carbohydrates 0.2 0.10 waste water from root washing, Protein 2.3 0.34 after the washer/husker has Phosphorus 0 0.01 removed soil and peelings and the Calcium 0.1 0.03 Potassium 0.3 0.06 water is decanted or filtered. The 3 Lipids 0.6 0.35 average factory volume is 2.62 m . Fiber 8.3 2.06 Waste water may also be extracted from pressed and grated cake in a. Numbers are rounded. flour manufacturing and from the b. Expressed in percentage of glucose. roots themselves. It is also a SOURCE: Escola Superior de Agricultura de Lavras byproduct of starch extraction (ESAL), unpublished data. (average factory volume is 3.68 m3).
The average composition of Liquid wastes manipueira sampled from different starch factories in São Paulo State is Lagoon mud. Table 7 also shows variable, as shown in the following the composition of sedimented lagoon list (numbers are rounded): mud and liquid wastes. Sometimes
229 Cassava Flour and Starch: Progress in Research and Development
Component Value existing in the disintegrated root mass. Humidity (%) 93.7 Dry matter (g %): The water used in starch factories Total solids 6.3 carries high concentrations of these Volatile solids 5.2 Starch 0 glycosides (linamarin and Soluble carbohydrates 0.5 lotaustralin) (Sobrinho, 1975). They Lipids 0.5 are hydrolyzed by linamarase enzyme Ash 1.1 and acid, making the cyanide a free Crude nitrogen 0.5 radicle (CN) (Williams, 1979). Fiber 0.3 Lignin 6.0 According to Sobrinho (1975), Free cyanide 43.7 liquid waste thrown onto soil or into Total cyanide 444.0 waterways causes pollution. If the Dry matter (ppm): pollution rate of starch factories is Phosphorus 160.8 expressed as biological oxygen Potassium 1,863.5 demand (BOD) over 5 days, at 20 °C, Calcium 227.5 and calculated as 24 g per habitant Magnesium 405.0 per day, it would be equivalent to that Iron 15.3 caused by 150-250 habitants per Copper 1.1 day—very high. In Santa Catarina Zinc 4.2 State, the pollution caused by these Manganese 3.7 wastes corresponds to 460 habitants Sulfur 19.5 Boron 5.0 per day (Anrain, 1983).
Chemical oxygen demand 6,365.5 Conclusions Volatile acidity (mg acetic acid/L) 2,703.7 Cassava wastes can be used in Alkalinity different ways. The solid residues can (mg bicarbonate/L) 1,628.0 be used as animal feed; the literature shows that cassava waste can replace C/N ratio 7.6 a part or all of the feed components. Manipueira can be used in agriculture C/P ratio 34.4 as a herbicide, nematicide, insecticide, or fertilizer. Anaerobic Titratable acidity (ml NaOH N%) 3.3 digestion is well studied in Brazil and is more advantageous than aerobic pH 4.1 digestion. Manipueira comes from flour industries, and the best processing method uses the separated phases reactor. We now need to Cyanogen content tends to be study how to optimize the acidic high, but varies according to cultivar. phase. The organic load is also high, and varies with the type of processing Cassava waste can also be used used (Table 8). All residual starch is for biomass production. The yeast removed from manipueira before Trichosporon sp. can be isolated by treatment. It has most soluble and natural fermentation with a some insoluble substances in cyanide-resistant respiration suspension and this residue carries pathway, and potentially can produce almost all the cyanogenic glycosides both a proteinic and a fat biomass.
230 Cassava Wastes:...
Table 7. Chemical composition of different types of cassava wastes, averaged over several analyses. Numbers are rounded. Dashes indicate no data were available.
Componenta Type of waste
Farinhãob Varredurac Lagoon mud
Humidity (%) 11.7 - 4.9 Dry matter (g %): Soluble carbohydrates 1.1 - 61.4 Lipids 68.5 - 1.8 Nitrogen 1.7 - 0.1 Fiber 0.5 0.5 1.8 Lignin (% SV) - - 9.7 Dry matter (ppm): Free cyanide - - 0 Total cyanide - - 0 Phosphorus 70.0 70.0 540.0 Potassium 700.0 640.0 240.0 Calcium 130.0 90.0 140.0 Magnesium 60.0 50.0 60.0 Iron 41.0 32.0 23,800.0 Copper 2.0 3.0 63.0 Zinc 8.0 8.0 75.0 Manganese 20.0 18.0 105.0 Sulfur 30.0 30.0 46.0 Boron 20.0 7.0 14.0 pH 5.4 - 5.4 Titratable acidity (ml NaOH N %) 3.7 - 3.9 a. No data were available for volatile solids, ash, and starch. b. Farinhão = solid waste made of pieces of cassava roots and inner peels. c. Editor’s note: No explanation of this term was provided by the authors.
Table 8. Composition of extraction water (mg/L) The microorganisms can also be from the Fleischmann-Royal factory, used to produce such biomasses as Conchal, São Paulo State, Brazil. organic acids (citric or lactic), Component Range measured biological insecticides, and enzymes. Chemical oxygen demand 6,280 -51,200 Biological oxygen demand 1,400 -34,300 Solid wastes also have a Total solids 5,800 -56,460 potential use for foodstuffs. The Soluble solids 4,900 -20,460 Suspended solids 950 -16,000 production of high-fiber biscuits Fixed solids 1,800 -20,460 from bagasse is being studied at the Organic matter 1,500 -30,000 Faculdade de Ciências Agronômicas Reducing sugars 2,800 -8,200 (FCA) of the Universidade Estadual Total phosphate 155 -598 Paulista (UNESP). Total nitrogen 140 -1,150 Ash 350 -800 Sedimentable solids (1 h) 11 -33 Cyanide content 22.0 -27.1 pH 3.8 -5.2
SOURCE: Lamo and Menezes, 1979.
231 Cassava Flour and Starch: Progress in Research and Development
References Motta, L. C. 1985. Utilização de residuos de industrias de farinha de mandioca em digestão anaerobia. Thesis for Anrain, E. 1983. Tratamento de efluentes de Master of Agriculture. “Julio de fecularia em reator anaeróbico de Mesquita Filho,” Universidade fluxo ascendente e manta de lodo. In: Estadual Paulista, Botucatu, SP, Anais do XII Congreso Brasileiro de Brazil. 130 p. Engenharia Sanitaria Ambiental, Balneário de Camburiu. Fundação de Nartey, F. 1981. Cyanogenesis in tropical Amparo à Tecnologia e ao Meio feeds and feedstuffs. In: Ambiente, Balneário de Camburiu, Vennesland, B.; Conn, E. E.; SP, Brazil. p. 1-21. Knowles, C. J.; Westley, J.; and Wissing, F. (eds.). Cyanide in biology. Arguedas, P. and Cooke, R. D. 1982. Academic Press, London, UK. Concentraciones de cianuro residual p. 115-132. durante la extracción de almidón de yuca. Yuca Bol. Inf. (Cent. Int. Agric. Oke, O. L. 1968. Cassava as food in Nigeria. Trop.) 10:7-9. World Rev. Nutr. Diet. 96:227-250. Carvalho, V. D. and Carvalho, J. G. 1979. ______. 1969. The role of hydrocyanic Princípios tóxicos de mandioca. acid in nutrition. World Rev. Nutr. Inf. Agropecu. 5:82-88. Diet. 11:170-98. Cereda, M. P.; Brasil, O. G.; and Fioretto, Rogers, D. J. 1965. Some botanical and A. M. C. 1981. Actividade respiratória ethnological considerations of em microorganismos isolados de Manihot esculenta. Econ. Bot. líquido residual de fecularias. Paper 19(4):369-377. presented at the 11º Congresso Brasileiro de Microbiología, Sobrinho, P. A. 1975. Auto-depuração dos Florianópolis, Bazil. corpos d’agua. In: Curso Poluição das Aguas, São Paulo. Cooke, R. D. 1979. Enzymatic assay for Companhia de Tecnologia de determining the cyanide content of Saneamento Ambiental (CETESB), cassava and cassava products. Associação Brasileira de Engenharia Cassava Information Center, CIAT, Sanitária (ABES), and Banco Cali, Colombia. 14 p. Nacional de Habitação (BNH), São Paulo, SP, Brazil. Hegarty, J. V. and Wadsworth, G. R. 1968. The amount of iron in processed Sreeramamurthy, V. V. 1945. Investigations cassava (Manihot esculenta). J. Trop. on the nutritive value of tapioca Med. Hyg. 71:51-52. (Manihot utilissima). Indian J. Med. Res. 33:229-238. Jensen, H. L. and Abdel-Ghaffar, A. S. 1969. Cyanuric acid as nitrogen sources for Um novo caminho para a mandioca: Química microorganisms. Arch. Mikrobiol. y derivados. 1973. Amido (São Paulo) 67:1-5. 32:26-28.
Lamo, P. R. and Menezes, T. J. B. 1979. Williams, H. J. 1979. Estimation of hydrogen Bioconversão das águas residuais do cyanide released from cassava by processamento de mandioca para organic solvents. Exp. Agric. produção de biomassa. Col. Ital. 15(4):393-400. 10:1-14.
Martelli, H. L. 1951. Mandioca, planta de valor. A. Fazenda, NY. 46:40.
232 Cassava Starch Extraction:...
CHAPTER 26
CASSAVA STARCH EXTRACTION: A TYPICAL RURAL AGROINDUSTRY WITH A HIGH CONTAMINATION POTENTIAL
Olga Rojas Ch.*, Patricia Torres L.*, Didier Alazard**, Jean-Luc Farinet***, and María del Carmen Z. de Cardoso*
Abstract effluents. Its operating principle is based on immobilizing microorganisms Every year, about 5,500 t of starch are on a lignocellulose support. The produced in Colombia from about hydrodynamic characteristics of three 27,000 t of cassava roots. Starch types of supports—sugarcane bagasse, production usually involves simple bamboo, and paja de monte technology, consuming an average of (underbrush straw)—were determined 23 m3 of water per ton of cassava. in the laboratory. Paja de monte This generates a contaminating load showed the best characteristics. of about 180 kg of chemical oxygen demand (COD) per ton of roots. An These studies will be average of 13.5 t of COD is discharged complemented with the monitoring of into Colombian rivers each day. existing microflora as changes occur in operational parameters. Processing generates two liquid residues: the first results from the washing and peeling of cassava roots, Introduction and generally contains a large amount of inert material with low COD; the Agroindustrial processes generate second results from draining the large volumes of waste waters and starch sedimentation tank, and has a solid residues whose quality varies high contaminating load of COD and according to the process used. biochemical oxygen demand (BOD). Generally, farm activities use abundant water to wash and treat A pilot project was proposed to products, at which point the water is treat waste waters, using an anaerobic loaded with harmful elements and filter and a transfilter. The transfilter compounds. These are directly technology has been tested in France, discharged into rivers and streams, yielding good results with household representing a risk for the environment, and the reduced quality makes the water less suitable for other uses. * Facultad de Ingeniería, Universidad del Valle (UNIVALLE), Cali, Colombia. ** Institut français de recherche scientifique Colombia is a mainly agricultural pour le développement en coopération country, with small and medium-sized (ORSTOM), stationed in Cali, Colombia. *** Département des cultures annuelles (CA), agroindustries widely scattered. This CIRAD, Montpellier, France. makes conventional water treatment
233 Cassava Flour and Starch: Progress in Research and Development systems onerous to use, given the Waste Waters from Cassava small volumes of products processed. Starch Extraction But versatile water treatment systems are now available at low cost and are Production and identification of attractive alternatives within the reach waste waters of small industries. About 200 cassava-starch production The feasibility of applying factories are located in the Cauca transfilter systems (anaerobic Department, most in the north. Their processing) to purify these discharges annual consumption of cassava roots is being studied by the Universidad is about 27,000 t, from which they del Valle (UV), Cali, Colombia, in extract about 5,500 t of starch. Plant collaboration with the Institut français processing capacity ranges from 500 de recherche scientifique pour le to 2,500 kg fresh roots per day développement en coopération (Janssen and De Jong, 1981). (ORSTOM), France, and is financially supported by the European Union Cassava-starch extraction involves (EU). A pilot reactor will be located in several stages: root washing and a starch factory in the Cauca peeling, rasping, screening, starch Department. The Corporación sedimentation, and, for sour starch, Autónoma Regional del Valle del fermentation (Figure 1). Roots are Cauca (CVC) will build a pilot washed in a tank or drum. They can anaerobic filter at the same site, so also be peeled in a drum, but this both can be evaluated from technical operation removes only 60% to 70% of and economic viewpoints. the peel, the remainder being peeled
Cassava (1 t)
Wash water Peelings 180 kg
Peeled cassava (820 kg)
Waste water
Rasped cassava (820 kg) Water 3 Bran (20 m ) (60 kg) Starchy slurry (20 m3)
Sedimentation Waste water (15 m3) Starch (0.27 m3) Dried scum (26 kg) Dried starch (230 kg)
Figure 1. Characterization of waste water from cassava starch extraction.
234 Cassava Starch Extraction:... by hand. This first stage of washing The use of anaerobic digestion to and peeling generates the first waste purify waste waters from cassava waters. starch extraction
The roots are rasped, and the pulp The results of characterizing the sieved through a nylon mesh that drainage water from sedimentation covers the inside of the screening tanks permitted an analysis of the drum. The starchy slurry is left to possibility of applying anaerobic settle for 20 to 24 h in sedimentation treatment to this type of residue. The tanks, until the starch layer is 25 to average COD value (900 mg/L) is 30 cm thick. The liquid is drained and high compared with that of BOD discarded, and the extracted starch (300 mg/L), suggesting a high passes to fermentation tanks, which COD-to-BOD ratio and the presence of are completely filled and then covered a high COD content, resistant to with a thin layer of water. biological degradation. But the UV and Fermentation takes about 4 weeks CVC’s preliminary research indicates (Pinto, 1978). that this factor is less important in terms of anaerobic biodegradation. Use of solid residues When specifically tested to determine the percentage of organic matter When water is separated from starch biologically degradable under in the sedimentation tank, a layer of anaerobic conditions, the percentage of greyish material is formed over the biodegradability was found to be 83%. starch, called mancha by starch manufacturers. This film, or The results of waste water analyses proteinaceous fraction, can be easily show that a sufficient amount of removed and dried. It is frequently nitrogen, a major element in biomass used as animal feed and is widely growth, is present in the residues. But accepted in the market. the amount of phosphorus, another essential macronutrient, is deficient Characteristics of waste waters (Table 1).
Waste water results from two The pH of drainage water from the processing stages: the washing of sedimentation tank ranges from 3.9 to peeled cassava and the draining of the 4.7, which means the residue must be sedimentation tanks (Figure 1). The neutralized before being fed to the former contains a large amount of inert reactor. material and has a low COD, and the latter, high organic loads of BOD and The low cyanide concentration in COD. the waste water (average 2.12 mg/L) suggests that the microbial biomass Analyses of waste water samples can adapt to this inhibitor. taken from sedimentation tanks at Methanogenic bacteria first react by different starch factories were carried reducing methane (CH4) production, out by the UV and the CVC. Average but, within a few days, they adapt to values were obtained to indicate the the cyanide and finally decompose it. approximate composition of such water. According to this information, Based on this finding, the UV and the volume of waste water discharged the CVC conducted studies to see if per processing plant per day ranges anaerobic processes are applicable for from 18 to 48 m3. The average overall treating this type of discharge contaminant load is about 13.5 t of (Table 2). Additional studies are now COD per day, or 3.45 t of BOD per day. being conducted on a pilot scale.
235 Cassava Flour and Starch: Progress in Research and Development
Table 1. Characteristics of waste waters resulting from cassava starch extraction (average values).
Parameter Average value Rangea
b COD (mg O2/L) 9,100 4,000 - 12,800 c BOD (mg O2/L) 3,100 1,500 - 8,600 COD/BOD (ratio) 2.9 - Cyanides (mg CN-/L) 2.12 1.2 - 4.04 Total solids (mg/L) 5,740 2,680 - 10,020 Volatile solids (mg/L) 4,870 2,020 - 9,320 Total organic carbon 2,420 870 - 5,300 pH (units) - 3.9 - 4.7 Temperature (°C) - 19 - 22 Sedimentation (ml/L) 29 15 - 47 Nitrogen (mg.N/L) 105 29 - 233 Phosphorus (mg.P/L) 2.34 0.3 - 6.0 a. This range is broad due to the amount of material processed. b. COD = Chemical oxygen demand. c. BOD = Biochemical oxygen demand.
SOURCE: Raddatz, 1986.
Table 2. Results of laboratory and pilot studies on the feasibility of anaerobic treatment of waste water from cassava processing, carried out by the Universidad del Valle and the Corporación Autónoma Regional del Valle del Cauca, Colombia.
Descriptiona 12-liter reactor 23-liter reactorb n Average ∂n-1 n Average ∂n-1
Effluent flow (ml/min)c 52 16.8 6.40 14 10.8 4.6 c CODAf (mg/L) 52 3,294 2,732 14 1,640 1,263 c CODEf (mg/L) 52 659 56 12 105 26 OVL (kg COD/m3.day)c 52 5.02 2.46 12 4.31 3.2 Removal COD (%)c 36 95 2 12 85.4 12.1 Biogas production (L/day) 53 16.4 8.4 - - -
a. CODAf = chemical oxygen demand in affluent flow; CODEf = chemical oxygen demand in effluent flow; OVL = organic volume load. b. The effluent was recycled by about 30%. c. These units refer to average values of the COD.
SOURCES: Escandón, 1988; Hernández, 1987.
Methanogenic activity in mud was particulate material present in the measured in the 12-liter reactor, waste water, and to fix those increasing significantly from an initial microorganisms responsible for biodecomposing waste organic matter. rate of 0.063 kg COD-CH4/kg VSS (volatile suspended solids) to a rate of The support bed decomposes with time so it has to be changed regularly; 0.188 kg COD-CH4/kg VSS. Although cyanide concentration was measured this also prevents silting. only a few times, it was calculated as decreasing by about 69%. Three operations occur simultaneously within the transfilter: (1) waste waters are purified by Transfiltering filtration and the organic material present in the waste is digested; This is a type of anaerobic treatment, (2) biogas (an energy resource) is using a lignocellulose base to filter produced; and (3) the lignocellulose
236 Cassava Starch Extraction:... material (a solid waste appropriate for de monte. No load loss was observed compost) is digested. Figure 2 is a in bamboo (Gotin, 1993). Technically, diagram of a transfilter reactor any of these materials can therefore be (Farinet, 1993). used, if due attention is paid to the operating criteria. The UV is conducting laboratory research on the transfilter process To complement the research on based on waste waters from cassava types of support, further studies on starch extraction. A pilot reactor will the filtration capacity of paja de monte later be built at a starch factory in the will be made at a pilot starch factory. Cauca Department. The aim is to determine the maximum compression of the support at which So far, with sugarcane bagasse, optimal filtration efficiency is obtained paja de monte, and bamboo as support for a given volume and period in beds, the following hydrodynamic relation to time of silting the filter. characteristics were determined: The supernatant effluent from the volume of waste water eliminated from starch sedimentation tanks will be the the supports, and load loss from clean waste water treated. water flowing through the filtering medium, as affected by water velocity To define constraints to designing and density of medium (compression). the pilot reactor, feasibility studies on methanizing the filter effluent will be Results showed very low load conducted in the laboratory, based on losses for higher velocities (35 m/h), previous results. and for stronger compressions (120 kg/m3 for bagasse and Bacterial microflora will also be 100 kg/m3 for paja de monte). studied for their composition, Maximum load loss was 7 cm for distribution, and nature of the bagasse 1 m long and 6.3 cm for paja different groups of bacteria involved
Waste water
Fermented (digested) Support support material
Biogas Biogas
Purified water
Piston
Figure 2. A transfilter reactor, used for the anaerobic treatment of waste water from cassava starch extraction. (From Farinet, 1993.)
237 Cassava Flour and Starch: Progress in Research and Development and their interactions. Considerable Gotin, G. 1993. Caractérisation knowledge is already available on the hydrodynamique de supports naturels metabolic pathways of the en vue de les employer en biofiltration. Thesis. Ecole nationale supérieure de microbiological process of anaerobic biologie appliquée à la nutrition et fermentation (hydrolysis, l’alimentation (ENSBANA), Dijon, acidogenesis, acetogenesis, and France. 43 p. methanogenesis). Hernández, L. I. 1987. Tratamiento anaerobio We will quantify and characterize de las aguas residuales del proceso de the active bacterial microflora producción de almidón de yuca y desechos del café. Convenio responsible for biodegrading the Universidad del Valle-Corporación effluent at each stage of the process. Autónoma Regional del Valle del The evolution, and the density, of Cauca (CVC), internal publication. each group of bacteria will also be Universidad del Valle, Cali, Colombia. assessed throughout the operation of the digestor. Janssen, W. and De Jong, G. 1981. Cassava and cassava starch: the production, processing, and marketing of cassava and sour cassava starch in Mondomo, References Colombia. CIAT, Cali, Colombia. 177 p. Escandón, F. 1988. Tratamiento de aguas residuales del proceso de Pinto, R. 1978. Extracción de almidón de yuca elaboración de almidón de yuca, en en rallanderías. ICA (Inst. Colomb. un reactor de flujo ascendente y Agropecu.) Informa 12(9):3-6. manto de lodos. Convenio Universidad del Valle-Corporación Raddatz, W. 1986. The possibility of anaerobic Autónoma Regional del Valle del treatment of wastes and Cauca (CVC), internal publication. wastewater from small and medium Universidad del Valle, Cali, agroindustries: sisal and cassava Colombia. starch production. Convenio de Cooperación, Corporación Autónoma Farinet, J. L. 1993. Traitement des eaux Regional del Valle del Cauca (CVC)- usées par le procédé transfiltre. Deutsche Gesellschaft für Technische Rapport d’essais sur prototype. Zusammenarbeit (GTZ). CVC, Cali, Département des cultures annuelles Colombia. (CA), CIRAD, Montpellier, France.
238 SESSION 5:
TECHNOLOGY DEVELOPMENT Improving Cassava Sour Starch Quality in Colombia
CHAPTER 27
IMPROVING CASSAVA SOUR STARCH QUALITY IN COLOMBIA1
C. Brabet*, G. Chuzel**, D. Dufour*, M. Raimbault†, and J. Giraud††
Introduction Bread-making potential (BMP) is the main criterion of quality for sour Fermented or “sour” starch extracted starch and is defined as the ability of from cassava is used in Colombia to the starch to swell during baking prepare traditional, gluten-free, (Laurent, 1992). cheese breads such as pandeyuca and pandebono. Starch extraction Although quality and rapidity are consists of peeling, washing, and two major issues in cassava starch grating fresh cassava roots. The pulp production, sour starch is still is then screened under running water produced according to traditional to obtain starch milk or lechada. The methods. Hence, sour starch is starch is then sedimented out and highly variable in product quality, placed into wooden or tiled tanks limiting its use in food industries. (about 1 m3), where it ferments naturally over 20 to 30 days under Fermentation and sun-drying anaerobic conditions and at an critically influence the BMP of sour average temperature of 21 °C. The starch (Brabet and Dufour, 1996; resulting sour starch is then Larsonneur, 1993). Developing sun-dried to obtain a stable product adequate control of and suitable with 10%-15% moisture, and is practices for these two processing marketed (Brabet and Dufour, 1996; steps would help stabilize and Jory, 1989). improve sour starch’s economic value and strengthen the status of this agroindustry.
Cassava processors sometimes improve sour starch quality by * CIRAD/SAR, stationed at the Cassava inoculating batches with surface Utilization Section, CIAT, Cali, Colombia. water from fermentation tanks in ** CIRAD/SAR, stationed at the Faculdade de Ciências Agronômicas (FCA), Universidade which good quality products have Estadual Paulista (UNESP), São Paulo, been produced. But this practice still Brazil. results in irregular quality of sour † Institut français de recherche scientifique pour le développement en coopération starch. (ORSTOM), stationed in Cali, Colombia. †† Laboratoire de microbiologie et biochimie We therefore studied the natural industrielles (GBSA), Université de fermentation of cassava starch in Montpellier II, Montpellier, France. detail, in an attempt to relate the 1. No abstract was provided by the authors. nature of microflora and their effect
241 Cassava Flour and Starch: Progress in Research and Development on final product quality. We then 1988; Cárdenas and de Buckle, 1980; carried out a cassava starch Larsonneur, 1993; Nakamura and inoculation trial, using amylolytic Park, 1975). lactic acid bacteria (ALAB), isolated and selected from previous Effect of a starter culture on fermentation kinetic studies. Our cassava starch fermentation and purpose was to standardize product quality quality and reduce fermentation time. A fermentation with starch We also carried out studies to inoculation was carried out at the confirm the role of sun-drying in the “SDT Agroindustrial,” a acquisition of BMP, and to determine starch-processing plant in La the key factors responsible. The trials Agustina, Cauca Department, involved sun-drying kinetic studies, Colombia, using cassava variety oven-drying at 40 °C and at 55 °C, CM 523-7. An amylolytic lactic acid drying under cover, oven-drying at bacterial strain, ALAB 20, used for 40 °C under ultraviolet (UV) light, and the starch inoculation trial, was drying with water added. isolated from a previous natural cassava starch fermentation and identified as Lactobacillus crispatus, Cassava Starch Fermentation using the Gómez (1993) API 50CH system. Flores (1993) studied the Natural fermentation physiological parameters of this ALAB 20 strain during a lactic acid Natural fermentation of cassava fermentation on an MRS-starch starch is characterized by the medium in a bioreactor. (The glucose presence of a predominantly lactic in the medium was replaced by acid flora (108-109 cfu/g dry matter of soluble starch.) starch), confirmed by the rapid and drastic decrease of pH (7 to 3.5 in The fermentation tank was 5 days), while total acidity increases partitioned into two: one part for because of a mainly lactic acid natural fermentation and the other production (Brabet and Dufour, for inoculated-starch fermentation. 1996). Lactic acid flora has an active Inoculated and noninoculated catabolism but its level is constant lechadas (aqueous starch during fermentation. suspensions) were first sampled. Then, samples of inoculated and At the start of fermentation, noninoculated starch were taken at 1, starch is the main source of 2, 3, 4, 5, 7, 10, 14, and 20 days of fermentable sugar. Gómez (1993) fermentation. isolated 75 lactic acid bacterial strains, exhibiting good amylolytic Changes in amylolytic and activity, from natural cassava starch total lactic acid flora. Total lactic fermentation. This ALAB strain bank acid flora on MRS medium showed no is currently being molecularly and significant difference between biochemically characterized. inoculated and noninoculated starch (Figures 1 and 2). This flora reached Previous works have shown 108-109 cfu/g of dry matter of starch modifications of cassava starch on the second day and remained physicochemical and rheological constant until the end of characteristics during fermentation fermentation. In contrast, as a (Brabet and Dufour, 1996; Brabet proportion of total flora, amylolytic and Mestres, 1991; Camargo et al., flora on MRS-starch medium (MRS
242 Improving Cassava Sour Starch Quality in Colombia medium where glucose was replaced pH and lactic acid production. by 20 g/L of soluble starch) were in In the inoculated-starch fermentation, a higher proportion in inoculated acidification was more notable during starch than in noninoculated the first 5 days of fermentation, but
(Figures 1, 2, and 3). Furthermore, pH value finally stabilized at 3.5 (pKa flora were heterogenous during the of lactic acid) in both fermentations natural fermentation, whereas the (Figure 4). The inoculated inoculated fermentation resulted in fermentation produced slightly more a predominance of the ALAB 20 lactic acid (Figure 5) during the first strain. days of fermentation.
10 120
100 9 80 8 60 7 40
6 20
Log (cfu/g dry matter of starch) 5 0 0 5 10 15 20 25 Proportion of amylolytic flora (%) 0 5 10 15 20 25 Days of fermentation Days of fermentation
Figure 1. Changes in anaerobic microflora on Figure 3. Evolution of amylolytic flora as MRS and MRS-starch media in proportion of total flora on natural fermentation. ( = total lactic MRS-starch medium during cassava acid flora on MRS agar; = total flora starch fermentation. ( = natural on MRS-starch agar; = amylolytic fermentation; = inoculated-starch flora on MRS-starch agar.) fermentation.)
10 6.0
5.5 9 5.0 8 4.5 pH 7 4.0
6 3.5
Log (cfu/g dry matter of starch) 5 3.0 0 5 10 15 20 25 0 5 10 15 20 25 Days of fermentation Days of fermentation
Figure 2. Changes in anaerobic microflora on Figure 4. Evolution of pH during cassava starch MRS and MRS-starch media in fermentation. ( = natural inoculated-starch fermentation. fermentation; = inoculated-starch ( = total lactic acid flora on MRS fermentation.) agar; = total flora on MRS-starch agar; = amylolytic flora on MRS-starch agar.)
243 Cassava Flour and Starch: Progress in Research and Development
12 Sour starch specific BMP increased from 2 cm3/g (wet starch) to at least 10 5 cm3/g in 4 h of sun-drying 8 (Larsonneur, 1993). The same starch sample, when oven-dried at 40 °C 6 (slow drying) or 55 °C (rapid drying), 4 or dried under cover for 8 h, did not expand (specific BMP of 2-2.5 cm3/g). dry matter of starch) 2 Lactic acid (mmol/100 g These results demonstrate the 0 0 5 10 15 20 25 need for sun-drying if sour starch is Days of fermentation to acquire BMP, and the importance of solar radiation. The results also Figure 5. Evolution of lactic acid content during explain why Brazilian plants cassava starch fermentation. ( = natural fermentation; producing cassava sour starch do not = inoculated-starch fermentation.) artificially dry starch during the rainy season but ferment it instead for various months until the dry season 6 arrives. /g) 3 Oven-drying trials of sour cassava 5 starch at 40 °C and under a UV lamp (Cole-Palmer, G-09817-20, 4 W, 4 254 nm and 366 nm) were conducted for 8 and 16 days. Under UV radiation, the sour starch’s capacity 3 for bread making increased to a value Specific volume (cm close to that of the sun-dried starch 2 control, whereas oven-dried samples 0 5 10 15 20 25 expanded little: Days of fermentation
Figure 6. Evolution of cassava starch Treatment Bread-making bread-making capacity during potential (cm3/g) at: fermentation. ( = natural fermentation; = inoculated-starch 8 h 8 days 16 days fermentation.) Sun-drying 6.82 6.82
Bread-making potential of Oven-drying at 40 °C 2.46 3.18 starch. Inoculation of cassava starch with ALAB 20 allowed the final BMP Oven-drying at 40 °C to be reached 10 days earlier, and under UV: compared with natural fermentation. But the final BMP of the starch was 254 nm 3.94 4.95 not improved (Figure 6). 366 nm 3.78 4.75
Sun-Drying Cassava Sour These results show that UV Starch radiation is one of the different types of sun radiation able to develop the Importance of ultraviolet radiation BMP of cassava sour starch. Compared with 8 h of sun-drying, the Kinetic studies of drying cassava sour lengthy period (8 and 16 days) needed starch in the sun (8 h) were realized. to increase the bread-making capacity
244 Improving Cassava Sour Starch Quality in Colombia of sour starch may be explained by The preliminary results of starch the low power (4 W) of the UV lamp inoculation trial demonstrated that used. the use of ALAB 20 as a starter culture helped reduce fermentation The role of water in sun-drying time. Replicated starch inoculation sour starch trials, using the same strain, will be undertaken to confirm these results. Water content of cassava sour starch Other lactic inocula will also be during sun-drying plays an important investigated for reducing fermentation role in improving the starch’s time and improving cassava sour bread-making capacity. For example, starch quality. cassava sour starch oven-dried at 40 °C for 8 h, then rehumidified to From the results cited above, the 50% and sun-dried for another 8 h, concept of an artificial drying had a higher bread-making capacity apparatus, using UV radiation and (5.10 cm3/g) than the same starch controlling starch moisture, can be sample dried under the same visualized. This would make conditions but without the additional standardizing sour starch drying and water (3.75 cm3/g). quality possible, which would no longer be at the mercy of the weather. Better results are obtained (7.4 cm3/g) if sour starch is sun-dried Studies are being conducted to at 40 °C for 8 h, then sun-dried for evaluate the influence of cassava another 8 h, but with water added variety and root storage on sour every hour for 3 h. In contrast, the starch quality. Climatic conditions expansion of the starch in the and the water used during production sun-dried control (8 h) was may also have effects. 5.03 cm3/g. Acknowledgments Conclusions We wish to thank J. Mayer and To improve the quality of cassava A. L. Chaves (Biotechnology sour starch, the following Laboratory, CIAT, Cali, Colombia) for recommendations should be made to their cooperation in analyzing organic the rallanderos (cassava sour starch acids, using high-performance liquid producers): chromatography (HPLC). We also thank F. Alarcón (CIAT) and (1) To ferment. Starch should be A. Beitz (Universidad del Valle, Cali, fermented for at least 20 days. Colombia) for their active The pH should be controlled at participation in the starch inoculation 3.5. The fermentation tank should trials. We specially thank A. L. Jaime be covered with about 5 cm of (Universidad del Valle) for her help. water to ensure anaerobic conditions and lactic acid fermentation. References (2) To dry. Sour starch should be dried under sunny conditions. Brabet, C. and Dufour, D. 1996. El almidón Starch samples should be turned agrio de yuca: producción y estudios de los propiedades fisicoquímicas. In: over to ensure exposure of all Proceedings of the Simposio en starch granules. Carbohídratos, del 4 al 6 octubre 1993, Quito, Ecuador. p. 197-203.
245 Cassava Flour and Starch: Progress in Research and Development
______and Mestres, C. 1991. Evaluación Jory, M. 1989. Contribution à l’étude de deux de las modificaciones estructurales processus de transformation du del almidón de yuca durante la manioc comportant une phase de fermentación: medida de la fermentation: le gari au Togo, viscosidad intrínseca y técnica de l’amidon aigre en Colombie. Mémoire cromatografía de permeación en gel. de Mastère en technologie alimentaire In: Proceedings of the taller “Avances régions chaudes. Ecole nationale sobre Almidón y Yuca”; abstracts, supérieure des industries agricoles et 17-20 June, Cali, Colombia. CIAT, alimentaires (ENSIA) and CIRAD, Cali, Colombia. p. 1-6. Montpellier, France. 45 p.
Camargo, C.; Colonna, P.; Buleon, A.; and Larsonneur, S. 1993. Influence du séchage Richard-Molard, D. 1988. solaire sur la qualité de l’amidon Functional properties of sour cassava aigre de manioc. Projet de fin d’études. (Manihot utilissima) starch/polvilho Génie biologique, produits biologique et azedo. J. Sci. Food Agric. 45:273-289. alimentaires, Université de technologie de Compiégne, France. 87 p. Cárdenas, O. S. and de Buckle, T. S. 1980. Sour cassava starch production: a Laurent, L. 1992. Qualité de l’amidon aigre de preliminary study. J. Food Sci. manioc: validation d’une méthode 45:1509-1512, 1528. d’évaluation du pouvoir de panification et mise en place d’une épreuve Flores, C. 1993. Estudio preliminar del descriptive d’analyse sensorielle. comportamiento fisiológico y Projet de fin d’études. Génie biologique, enzimático en bioreactor de cuatro produits biologiques et alimentaires, bacterias amilolíticas aisladas del Université de technologie de almidón agrio de yuca (Manihot Compiégne, France. 68 p. esculenta Crantz) en Colombia. Informe de trabajo. CIAT, Cali, Nakamura, I. M. and Park, Y. K. 1975. Some Colombia. 22 p. physico-chemical properties of fermented cassava starch (“polvilho Gómez, Y. 1993. Bacterias lácticas azedo”). Starch/Stärke 27(9):295-297. amilolíticas presentes en la fermentación del almidón agrio de yuca. Thesis. Facultad de Ciencias, Departamento de Biología, Universidad del Valle, Cali, Colombia. 69 p.
246 Investigating Sour Starch Production in Brazil
CHAPTER 28
INVESTIGATING SOUR STARCH PRODUCTION IN BRAZIL
R. C. Marder*, R. de Araujo Cruz**, M. A. Moreno***, A. Curran*, and D. S. Trim*
Abstract countries. Areas identified for future development and improvement In sour starch producing countries include quality definition and such as Brazil and Colombia, most standardization, marketing and production is from small and promotion, and pollution abatement medium-sized plants. If the sector is measures. to develop, it must adapt to changing circumstances, environmental factors, and market demand for improved Introduction product quality. Data on current processing operations are essential for Production of sour starch identifying and prioritizing development and modernization In Brazil, sour starch (polvilho azedo) needs. is manufactured principally in the State of Minas Gerais (MG), with This paper presents the results additional production in São Paulo of a detailed, in-depth investigation and Paraná States. Plants are of sour starch production in southern typically small to medium-sized, Brazil. We first describe the processing about 10-20 t/day of major processing operations: root roots, although larger plants can preparation, disintegration, screening process as many as 50 t/day. for fiber removal, sedimentation, and drying. Then we discuss the inputs An estimated 80 plants operate in and outputs for each operation, the municipalities of Cachoeira da the composition of products and Minas and Conceição dos Ouros, in intermediates within the process, the region of Pouso Alegre, southern and, in particular, the volume and MG. Typical plants produce about composition of waste waters—a factor 3 t/day of starch, although some of increasing environmental concern. larger plants produce 10-15 t/day. The Empresa de Assistência Técnica e The data are then related to starch Extensão Rural (EMATER) (personal production technology used in other communication, 1993) suggests that the region produced about 18,000 t in 1986, and is now producing 12-13 thousand tons per year. * Natural Resources Institute (NRI), Kent, UK. ** APTA Consultancy Group, São Paulo, Brazil. *** Universidad del Valle (UNIVALLE), Cali, Sour starch production is also Colombia. concentrated around Divinópolis
247 Cassava Flour and Starch: Progress in Research and Development where about 10 small plants operate, processing methods. Before changes each employing three to four people can be made, accurate and detailed and producing more than 100 t of data are needed on current processing starch per year (EMATER, personal operations. Cereda and Takahashi communication, 1993). These exist (Ch. 25, this volume) have gathered alongside more than 100 very small information on processing operations starch production units, based on in farinha and native starch industries family farms, which sell to the local in Brazil. But comprehensive data are market, supermarkets, bakeries, and unavailable on operations and households. The total 1985 problems experienced in small and production in the Divinópolis region medium-sized sour starch plants. We, was estimated to be about 10,000 t. therefore, conducted a detailed Current production is probably below analysis of plant operations in two this figure if trends mirror those of the plants in Minas Gerais. Pouso Alegre region. No apparent change has occurred in the number of the region’s plants during the last Production Technology 3 years. The small- to medium-scale Sour starch is used in certain production of sour starch in Brazil is snacks, mainly pão de quiejo and schematically similar to that of sour biscoitos, on sale in public eating starch in Colombia as described by places such as cafés and bus stations. Salazar de Buckle et al. (1971) The market for these products is (Figure 1). stagnating, because of increasing competition from other snack Lorry loads of fresh roots are products and the effects of the current delivered to the plant and fed into a economic climate on consumer rotary washer fitted with overhead spending. However, pão de quiejo has water sprays for part of its length. As recently begun to be marketed well as washing off dirt and debris, through a fast-food chain which the tumbling action of the roots specializes in the product, and as they pass along the washer also supermarkets have begun stocking it removes most of the bark. Washed as a frozen product. roots are transferred to the hopper-fed, root disintegrator, via Although this expanded market an inspection conveyor, at which an has resulted in a more buoyant operator cuts up excessively large demand for sour starch, it has not had roots, and removes remaining bark the kind of effect on the industry that and stems. might have been expected. In Paraná State, especially, producers of pão de All plants employ similarly quiejo are increasingly replacing sour constructed disintegrators known as starch with industrially produced, the “Jahn rasper” (Grace, 1977; unfermented, sweet starch (fecula), or Radley 1976). This machine consists sun-dried sweet starch (polvilho doce). of a hollow, cylindrical drum, with tooth-edged steel blades sandwiched If the local sour starch industry is between local hardwood slats fixed to survive, it must adapt to changing longitudinally to its surface. The circumstances—e.g., increased drum is mounted between two demand for an improved quality circular steel endplates on a central product, increasing costs of inputs, shaft and housed inside a steel and concern for environmental casing, the base of which includes a conservation—by improving its screening plate.
248 Investigating Sour Starch Production in Brazil
Roots
Water Washing Waste water
Disintegration Recycled liquor Water
Separation Separation Pulp (First stage) (Second stage)
Starch Water milk Water Screening
Sedimentation Waste water
Water Fermentation
Milling
Drying Water vapor
Milling
Packaging
Figure 1. Sour starch manufacture in a typical plant in Minas Gerais State, Brazil.
Recycled liquor from the starch tapering from front to back. The separators is continuously fed into the conical screen is a metal frame disintegrator. The resultant slurry of covered with a nylon mesh. The crushed roots passes through the narrow end of the cone is closed with screening plate into a sump tank from a fixed metal plate connected to the which it is pumped to the separators. drive shaft. Slurry is pumped into the center of the separator (toward the All plants employ a two-stage fixed plate) and forced through the separation process to remove the screen to an outlet at the bottom of liberated starch from the fibrous pulp the casing into a sump tank. Water is (massa). The majority of plants sprayed into the slurry from jets employ two centrifugal separators, positioned around the screen. which have replaced the traditional, rotating brush-and-screen washers. In the sump tank, the slurry receives extra water to facilitate The centrifugal separator consists pumping it over a flatbed reciprocating of a rotating conical screen, housed screen to remove any remaining fiber inside a shaped, mild-steel casing, (larger plants employ an additional
249 Cassava Flour and Starch: Progress in Research and Development centrifugal separator). The slurry then sacks laid on raised, drying tables, enters a second separator for further usually made of bamboo. The drying starch extraction. Liquor discharged starch is agitated manually at regular from the second separator is returned intervals. When dry, the starch is to the disintegrator, and the collected, milled to a powder, and suspension of pulp, or “starch milk,” packaged into 50-kg bags or, in some is discharged to storage tanks. plants, into packs for direct sale to retailers. The milk then flows into sedimentation channels or “tables” (Bruinsma et al., 1981). Dimensions Monitoring Plant Operations for the channels vary considerably from plant to plant: in length, from Measuring process parameters and 150 to 200 m; in width, from 0.6 to sampling procedures 1.0 m; and in depth, from 0.4 to 0.6 m. The channels are usually lined With the agreement and cooperation with ceramic tiles because both starch of plant management and staff, and starch milk attack concrete. The processing operations at two plants channels are roofed to protect the were monitored for 3 weeks. starch from rain or sunlight. Monitoring activities were:
The milk is directed into one end (1) Measuring water flows within of the channels and the supernatant processing operations to determine liquor flows over a weir at the other water consumption at each stage; end to be discharged as waste water (2) Periodic sampling of fresh roots, into nearby watercourses, seepage disintegrator slurry, starch milk, pits, or infiltration channels. waste fibrous pulp, fermented and dried starch; After overnight settling, (3) Sampling of water supplies and supernatant remaining in the generated effluents throughout the sedimentation channels is discharged process to characterize pollution by removing the weir. The surface of loads. the settled starch is sometimes washed to remove those uppermost During monitoring, no attempt layers containing high concentrations was made to influence plant of dirt, protein, and fiber impurities. management and staff in their work. Over several days, the channels are allowed to fill with successive layers of starch until space is available in Sample analysis the fermentation tanks. The starch is then dug out of the channel, Moisture content of root, starch cake, transferred to the tanks, covered with and pulp samples were determined by water, and left to ferment for a oven drying at about 45 °C to constant minimum of 30 days. The tanks are weight. Dried samples were stored also lined with ceramic tiles and are and later analyzed for starch content, usually constructed in series adjacent using enzyme hydrolysis (AOAC, 1965) to the sedimentation channels. They, and crude fiber (Harris, 1970). too, are roofed to prevent exposure to sunlight and rain. Immediately after collection, the pH of all water and effluent samples After fermentation, the starch is was measured with a hand-held meter removed from the tanks, broken up (CIBA Corning Diagnostics Ltd., with a spike mill, and dried on hessian Halsted, UK). The samples were then
250 Investigating Sour Starch Production in Brazil taken to a local laboratory and shaft, which was driven at 150 rpm by analyzed for chemical oxygen demand a 2.2-kW (3 HP) motor. In plant A, the (COD), and suspended and dissolved trough was fitted with an overhead solids. water spray for the latter two-thirds of its length, whereas in plant B, the spray covered only the last third. Results and Discussion The flow of roots through the Root washing washers was, in effect, the same for both plants at 0.55 kg/s of fresh Table 1 shows the proportions of dirt, roots. But plant A used a much larger bark, peel, and parenchyma in the volume of water for washing: about roots received at the two plants and 1.95 L/s (or 3.55 m3/t of roots), Table 2 shows the composition of the compared with 0.70 L/s (or 1.27 m3/t) washed roots. for plant B (Table 3). The washer’s performance at plant A, as measured The root washers employed in the by the percentage removal of bark, two plants had a similar design: a was considerably more effective (about semicircular, slatted trough, 7 m long 95%), compared with that of plant B with a 0.95-m diameter. It had fixed, (78% to 80%). At plant B higher levels 4-bladed paddles, mounted 0.3 m of dirt and bark fragments were visibly apart on an overhead, central rotating observable in the sedimented starch.
Large sweet-starch plants in Brazil and India employ similar washers. In Table 1. Composition (%) of residues from smaller Brazilian and Colombian washing fresh cassava roots at two plants, root washing is performed in plants producing sour starch, Minas batches, using rotating, slatted drums Gerais, Brazil. with a continuous supply of water. Component Plant A Plant B But in medium-sized plants in India, roots are passed through a flatbed Dirt 0.50 0.49 conveyor washer, removing only the Bark 2.35 1.84 dirt and leaving the bark (Trim et al., Peel 15.01 17.47 1993). For sago production, both the Parenchyma 82.14 80.20 bark and peel are removed manually.
Table 2. Composition of roots, starch, and pulp at two plants producing sour starch, Minas Gerais, Brazil.
Sample Component (% DM)a
Total Starch Crude Fat Protein Ash solids (%) fiber
Plant A: Washed roots 34.45 89.35 1.92 0.44 2.55 1.32 Dried starch 88.10 96.59 0.35 - - - Pulp 7.70 85.59 8.45 0.16 1.36 0.96
Plant B: Washed roots 36.85 90.11 2.16 0.19 2.68 1.10 Dried starch 88.73 96.43 0.41 - - - Pulp 7.23 82.21 12.14 0.24 1.79 1.26 a. (% DM) = percentage of dry matter.
251 Cassava Flour and Starch: Progress in Research and Development
Table 3. Total water consumption at two plants to that reported by Trim et al. (1993) producing sour cassava starch, Minas of 83% for an Indian sago plant. Gerais, Brazil. However, in the Indian plant, two Operation Water consumption perforated drum disintegrators were used in series to improve starch m3/t of m3/t of roots product extraction.
Plant A: The operation of the disintegrator Root washing 3.55 15.24 at plant B was much smoother, with Starch extraction 3.78 16.22 less notable strain on the motor, Total 7.33 31.46 because of variation in feeding the Plant B: roots. Furthermore, the plant operator Root washing 1.27 4.70 thought that the throughput of Starch extraction 4.50 16.67 roots in the disintegrator could be Total 5.77 21.37 increased, thus increasing maximum output.
Starch separation Root disintegration Plant A employed two identical The drums in the disintegrators at centrifugal separators, both the two plants were of similar belt-driven from a common 3.7-kW construction, 0.32 m in diameter and (5 HP) motor and rotating at 650 rpm. 0.28 m in width. The blades were The rotating conical screen in each longitudinally spaced, at about was 0.70 m in length, 0.25 m in 12 mm, around the circumference of diameter at the narrow end, and the drum. Each drum had 80 to 0.76 m at the wider end. It 85 blades. The disintegrators were was covered with nylon mesh both directly driven by an electric (PA-120-125/ASTM1). The steel motor and rotated at 2,500 rpm. casing was 1 m squared in front, However, plant A employed a smaller tapering to 0.5 m squared at the back. motor (11.2 kW or 15 HP) than did plant B (18.6 kW or 25 HP). Both Water was fed to the first plants employed 1.5-kW (2 HP) separator at 0.90 L/s and to the centrifugal pumps to transfer the second at 0.72 L/s. Fresh water was slurry from the disintegrator sump to also added to the sump tank between the separators. the separators at a rate of 0.44 L/s. The total water added was therefore The total solids content of the 2.06 L/s (3.78 m3/t of roots). Starch disintegrated root slurry at plant A milk was discharged from the was 8.2% and at plant B, 7.6%. first separator directly into the Although these values are similar, the sedimentation channel at a rate of disintegrator at plant B produced a 1.99 L/s with a concentration of solids much finer slurry, indicating a higher at 7.1%. degree of root maceration. This was reflected in the starch extraction Plant B used a single centrifugal efficiency (i.e., the fraction of starch separator, identical to those at plant released in disintegration) at plant A A, for the primary stage, and a (81%), compared with plant B (84%). rotating brush-and-screen washer for These figures are considerably higher than those quoted by Bruinsma et al. (1981) of 61% to 68% for small- to 1. ASTM = American Society for Testing and medium-scale production, but close Materials.
252 Investigating Sour Starch Production in Brazil the second stage. The operating 0.4 m deep. Plant B had four similarly speed of the centrifugal separator at constructed channels, each 45 m long, 760 rpm was higher than at plant A, 0.82 m wide, and 0.5 m deep. Both although using a similarly powered sets of channels had a weir, 0.15 m motor. high, at one end. The residence time for starch milk flowing into empty The brush-and-screen washer channels was 3.0 h for plant A and consisted of a semicircular, screened 2.4 h for plant B. The solids content trough (5.65 m long and 0.42 m in of batches of sedimented starch diameter), above which a shaft, removed from the channels averaged rotating at 530 rpm, was centrally 59.9% for plant A and 59.1% for mounted. Plastic brushes were plant B. spaced at 90 mm intervals along the shaft, which was rotated by a 2.2-kW In India, tanks are used instead of (2 HP) centrifugal pump. channels for sedimentation, largely because of historical reasons (Trim et Water was sprayed into the al., 1993). After overnight settling and separator at a rate of 0.74 L/s and removal of the supernatant liquor, the into the washer at 0.55 L/s; 1.20 L/s starch cake had a concentration of of water was fed into the sump solids at 50%, but after washing, the tank between the two. Total water concentration was 55%. consumption was therefore 2.48 L/s (4.51 m3/t of roots). Starch milk was Starch and crude fiber discharged from the washer at a rate concentrations of the settled cake in of 2.52 L/s with a concentration of the two plants were similar, averaging solids at 6.80%. 96.7% for starch and 0.3% for crude fiber (dry matter basis). The solids content of the waste pulp was 7.70% in plant A and 7.23% The changes occurring in the in plant B (Table 2). The starch starch as a result of fermentation are content of the pulp at plant A was the subject of much recent research 85.59% and at plant B, 82.21%. The (e.g., Brabet et al., Ch. 27, this higher concentration from plant A volume) but were not studied in this again indicates less efficient investigation. Although a minimum disintegration of the roots. Trim et al. fermentation time of 30 days is (1993) measured a starch necessary, starch often remained in concentration of 72% in the pulp the tanks at the two plants for longer discharged from a system of periods because of the lack of reciprocating screens. available drying space. Such prolonged fermentation had no The concentration of free starch in detrimental effect on starch quality. the waste pulp was very low at both The temperature of the fermenting plants (0.32% at plant A and 0.18% at starch at the two plants ranged plant B), indicating a high efficiency of between 12 and 13 °C. extraction of free starch from the pulp. Drying Sedimentation and fermentation Both plants employed traditional Plant A used six channels, drying tables, raised about 1 m from constructed side by side and the ground. They were essentially connected in series to minimize space bamboo mats (esteiras), 4.0 m long and ease unloading. Each channel and 1.2 m wide, tied to bamboo beams was 32 m long, 0.74 m wide, and mounted on wooden stakes. Plant A
253 Cassava Flour and Starch: Progress in Research and Development had 600 esteiras, with a total drying Material balance area of 2,800 m2, and plant B had 760 esteiras (3,650 m2). The fermented The material balance for the starch was spread on cotton sacks processing operations at the two stretched across the tables with a wet plants was calculated from the starch loading of about 1.8 to measured data of process flows and 2.0 kg/m2. from results of laboratory analyses (Figures 3 and 4). Figure 3 shows that In summer, drying may take 6 to the total mass flow of dried starch in 7 h, but in winter it may take 2 plant A was 23% and Figure 4, 27% in working days or 13 h. Starch that is plant B. A more accurate comparison still damp by the end of the day is is that of starch recovery efficiency— gathered up in cotton sacks and placed the fraction of starch in the roots in storage sheds overnight. recovered in the product. The overall starch recovery was about 67% for Figure 2 shows the drying curves plant A and 72% for plant B. for batches of starch dried at the two plants (moisture contents are given on Product quality a wet basis). As calculated from Table 2, the moisture content (dry Table 2 gives the composition of the basis) of the dried starch produced at starch products. The results indicate plant A was 11.9% and that at plant B, no significant difference in starch 11.3%. The dried starch contents were purity in products from the two 96.6% at plant A and 96.4% at plant B plants, especially in root washing, (dry matter basis) (Table 2). despite their different processing procedures. Many plants in the area are investing in drying tables made of wire Processors commonly define mesh within wooden frames. The mesh quality in terms of the degree of provides improved ventilation around whiteness and the acid taste of the the starch and so reduces drying time. sour starch, but no data exist to confirm that these criteria are linked to commercial value. Producers 50 believe quality improves the more the processing environment is clean, the 45 more water used, and the purer the 40 processing water. Spring water is usually preferred to well or river water. 35 The lower temperature of spring 30 water is also believed to improve 25 fermentation. Intense sunlight and agitated air movement around the 20 starch on a second or third day’s 15 drying may deteriorate quality by
Moisture content (% wb) encouraging growth of mold. 10
5 Water consumption and characteristics of waste water 0 0 12345678910111213 Drying time (hours) Plant A used more water for root washing (3.55 m3/t of roots) than did Figure 2. Sour starch drying curves at two plants 3 in Minas Gerais, Brazil. ( = plant A; plant B (1.27 m /t) (Table 3). = plant B.) However, plant A used appreciably
254 Investigating Sour Starch Production in Brazil less water for root disintegration and effluents from the plants. These data starch separation (3.78 m3/t) than confirm the highly polluting nature of did plant B (4.50 m3/t). Total water these waste waters. The COD of the consumption was 7.33 m3/t for plant waste waters from plant A was A, and 5.77 m3/t for plant B. The 4,800 mg/L and from plant B, flow of water recycled from the 3,500 mg/L. The CODs of the separators to the disintegrator was supernatant liquor discharged from marginally different in the two the sedimentation channels were plants: plant A recycled 3.50 m3/t 11,500 mg/L for plant A and and plant B, 4.22 m3/t. In sago 14,800 mg/L for plant B, that is, production in India (Trim et al., much higher than the 6,700 mg/L 1993), water consumption was noted in liquor discharged from 6.40 m3/t, of which 4.10 m3/t was sedimentation tanks in India (Trim et used for disintegration and al., 1993). separation. Analyses also indicated that the Table 4 shows the results of supernatant liquors contained analyses of the two principal significant levels of cyanide
Roots T-1000, W-637, S-299, N-64
Water Waste water Washing W-3550 T-3640, W-3591, S-18, N-31 Washed roots T-910, W-596, S-281, N-33
Disintegration
Root slurry T-4410, W-4038, S-327, N-45 Recycled liquor T-3500, W-3442, S-46, N-12
Water Separation W-3780 Pulp T-1150, W-1070, S-67, N-13 Starch milk T-3540, W-3306, S-214, N-20
Sedimentation Waste water T-3200, W-3171, S-15, N-14
Starch cake T-340, W-135, S-199, N-6
Fermentation
Starch cake
Water vapor Drying W-109
Dried starch T-233, W-28, S-199, N-6
Figure 3. Material balance, based on 1,000 kg of roots, for plant A in Minas Gerais, Brazil. (T = total mass flow; W = water flow; S = starch flow; N = flow of nonstarch components.)
255 Cassava Flour and Starch: Progress in Research and Development
Roots T-1000, W-617, S-324, N-59
Water Waste water Washing W-1270 T-1360, W-1313, S-21, N-26
Washed roots T-910, W-574, S-303, N-33
Disintegration
Root slurry Recycled liquor T-5130, W-4740, S-343, N-47 T-4220, W-4166, S-40, N-14
Water Separation W-4500 Pulp T-950, W-882, S-56, N-12 Starch milk T-4460, W-4192, S-247, N-21
Sedimentation Waste water T-4060, W-4032, S-14, N-14
Starch cake T-400, W-160, S-233, N-7
Fermentation
Starch cake
Drying Water vapor W-130
Dried starch T-270, W-30, S-233, N-7
Figure 4. Material balance, based on 1,000 kg of roots for plant B in Minas Gerais, Brazil. (T = total mass flow; W = water flow; S = starch flow; N = flow of nonstarch components.)
Table 4. Characteristics of waste waters at two plants processing cassava sour starch in Minas Gerais, Brazil.
Sample Characteristica
COD DS SS pH HCN (mg/L) (mg/L) (mg/L) (mg/kg)
Plant A: Waste waters 4,778 401 1,297 5.93 Supernatant liquor 11,538 1,516 7,351 5.11 43
Plant B: Waste waters 3,475 618 1,797 6.21 Supernatant liquor 14,778 3,370 4,979 5.38 62
a. COD = chemical oxygen demand; DS = dissolved solids; SS = suspended solids.
256 Investigating Sour Starch Production in Brazil compounds, measured at organized and the equipment usually 43-62 mg/kg. These values are much well maintained. Some significant higher than those measured in India changes in processing have been (20-35 mg/kg). The roots used in adopted over recent years, most India for sago production are peeled notably the introduction of centrifugal before disintegration, thus carrying separators for the recovery of starch away larger quantities of cyanogens. from the macerated roots. An effective means of technology transfer Effluent treatment exists through the localized nature of the industry, the local equipment The effluent problem is a major supply and maintenance workshops, environmental issue in both Pouso and plant workers setting up their Alegre and Divinópolis. Many plants own processing plants. discharge their effluent directly into small streams feeding the local river. Plant operators see the most Fish and animals have been killed by important issues as being: polluted watercourses, and the State Water Authority is concerned about Availability and price of cassava the dangers of polluting drinking roots; water supplies. Access to “soft” loans to finance working capital; Federal legislation requires that Labor costs; plants install effluent treatment Packaging costs; systems capable of removing at least Marketing and promotion; 85% of the pollution load. Some local Perception of improved quality by authorities have threatened legal consumers; action against plants that do not Efficient and cost-effective effluent install treatment systems, despite the treatment systems. fact that no effective treatment systems are available that are also Processors also consider economically feasible. In reality, fermentation and drying to be however, plant closures are unlikely processing bottlenecks. The long because of local socioeconomic fermentation periods tie up scarce factors, and pollution will continue working capital, and sun-drying is until cost-effective solutions are sometimes unreliable and requires found. considerable space. But, if improved technology for rapid fermentation and The most commonly used disposal artificial drying become reality, then systems include seepage pits (usually large-scale industrialists in other three pits used in series) or infiltration areas may be able to undercut channels, which allow water to seep small-scale producers in product through the soil. The solid material is price by having access to cheaper root removed periodically and used supplies and reaching economies of as fertilizer. Some plants use the scale. Such undercutting would effluent for irrigating their cassava mean the collapse of a large crop. The long-term effects of these proportion of the industry in Minas methods are unknown. Gerais.
The market for sour starch Conclusions products is growing slowly, but competition in supply is intensifying The two plants studied, and most of and quality is becoming more the others visited, were efficiently important. Producers in Minas
257 Cassava Flour and Starch: Progress in Research and Development
Gerais may well encounter future Bruinsma, D. H.; Witsenburg, W. W.; and problems as a result of increasing Wurdemann, W. 1981. Cassava. In: competition from new producers Selection of technology for food processing in developing countries. (especially in São Paulo State), who Centre for Agricultural Publishing and have greater financial resources, Documentation (PUDOC), Wageningen, access to higher levels of technology, the Netherlands. p. 113-158. and are located near cheap and abundant supplies of roots. Grace, M. R. 1977. Cassava processing. FAO plant production and protection series. Food and Agriculture Organization of Future priorities for research the United Nations (FAO), Rome. 155 p. should be concentrated in three areas: Harris, L. E. 1970. Determination of cell wall (neutral detergent fiber) and cell contents. In: Nutrition research (1) Product quality. Quality factors techniques for domestic and wild need to be clearly defined and animals, vol. 1. Utah State University, standards established. Logan, UT, USA. p. 2801-2802. Relationships between process inputs, operations, and quality Radley, J. A. 1976. Starch production factors need to be identified and technology. Applied Science Publications, London, UK. 587 p. evaluated. (2) Markets. Promotional efforts are Salazar de Buckle, T.; Zapata M., L. E.; required to expand consumer Cárdenas, O. S.; and Cabra, E. 1971. awareness of sour starch and its Small-scale production of sweet and specialized properties and uses. sour starch in Colombia. In: Weber, (3) Water pollution. Affordable E. J.; Cock, J. H.; and Chouinard, A. (eds.). Cassava harvesting and technology for water conservation, processing; proceedings of a workshop waste reduction, and treatment held at CIAT, Cali, Colombia. operations needs to be developed International Development Research to minimize pollution. Centre (IDRC), Ottawa, Canada. p. 26-32.
Trim, D. S.; Nanda, S. K.; Curran, A.; References Anantharaman, M.; and Nair, J. 1993. Investigation of cassava starch and AOAC (Association of Official Analytical sago production in India. Paper Chemists). 1965. Official methods presented at the International of analysis. 10th ed. Arlington, VA, Symposium on Tropical Root Crops, USA. 6-9 Nov., Thiruvananthapuram, India.
258 Implementing Technological Innovations...
CHAPTER 29
IMPLEMENTING TECHNOLOGICAL INNOVATIONS IN CASSAVA FLOUR AND STARCH PROCESSING: A CASE STUDY IN ECUADOR1
Vicente Ruiz*
Background de Asociaciones de Trabajadores Agrícolas, Productores y Procesadores Before 1985, the only cassava de Yuca (UATAPPY). This team copied processing technology known in and adapted some prototype Ecuador was mechanical rasping and equipment and tools on-site in the hand-sieving to extract starch from Association’s processing plants. The the roots. Since then, new products—cassava starch and flour— technologies have been introduced, were efficiently produced and and existing ones improved, to entered national and international increase processing efficiency and markets. open new markets for both cassava starch and flour. Flour Processing These new technologies include chipping, drying, and grinding Technology introduced from cassava roots to produce meal and Colombia flour from peeled cassava roots, and sieving coarse-grained flours to In late 1985, trials showed that produce fine ones. Improved cassava meal could be technically and equipment for starch processing economically produced, using a include raspers with saws, technology introduced from CIAT, continuous flow washer-peelers, Colombia. The technology consisted vibrating screens, and sedimentation of chipping, drying, and grinding channels. dried cassava. Chips, produced by a Thai-type, mechanical, disc chipper, In Manabí, Ecuador, a are dried on outdoor concrete floors participatory approach has been used and then ground in hammer mills. to facilitate the adoption of improved technologies. The first step was to Technology currently used by train the technical team of the Unión UATAPPY
In addition to cassava meal, three other types of flour are produced: white industrial flour, table flour, and * Unión de Asociaciones de Trabajadores sieved whole-grain flour. The Agrícolas, Productores y Procesadores de technology used to produce these Yuca (UATAPPY), Manabí, Ecuador. flours differs from that for cassava 1. No abstract was provided by the author. meal (Table 1). To produce white
259 Cassava Flour and Starch: Progress in Research and Development
Table 1. Comparison of steps in the processing of different cassava flours, once roots are received, using current technology, Manabí, Ecuador.
Process Flour (technique) Cassava White Table Sieved meala industrial flour flour whole-grain flour
Peeling (manual) X X X Washing (manual, mechanical) X X Chipping (Thai-type disc chipper) X X X X Drying (concrete floors) X X Drying (trays) XX Milling (hammer mill) X X X X Sieving (vibrating or centrifuge screen) X X Packaging (polypropylene) X X X X a. Original technology, introduced from Colombia. The other products are produced with more recent technology.
industrial flour, the roots are peeled mechanically with an engine-driven by hand before being fed to the wooden drum covered with a chipper. The rest of the process is the perforated zinc plate, then sieved by same as for cassava meal. To hand. Sedimentation is carried out in produce table flour, the roots are wooden or concrete tanks, and the peeled and washed before chipping, starch dried on concrete floors or on and then dried naturally on trays, or paper (Figure 1). artificially. Once the dried chips are ground, the resulting flour is sieved Technology currently used by through a vibrating or centrifuge UATAPPY screen. Sieved whole-grain flour is produced by passing the meal The UATAPPY is currently extracting through a vibrating screen as for cassava starch with mechanized table flour. technology developed with the technical assistance of CIAT and the Fundación Adelanto Comunitario Starch Processing (FACE), and with the financial support of the Fundación para el Traditional technology used in Desarrollo Agropecuario Ecuador (FUNDAGRO). Cassava roots undergo the following procedures: washing Manual starch extraction in Ecuador and peeling, in either batch or dates back about 50 years. continuous flow, with Brazilian-type Traditionally, to extract cassava washers; mechanical rasping with starch, roots are peeled and washed Brazilian-type saw blades; sieving, by hand, grated by hand or both by hand and vibrating screens;
260 Implementing Technological Innovations...
Roots received
Traditional technology Current technology batch system gravity system
Process Technique Process Technique
Peeling Manual
Washing Manual Washing Continuous-flow washer Batch washer
Grating Manual Rasping Rasper with blades Mechanized
Sieving Manual Sieving Mixed (manual and mechanical) Vibrating screen
Sedimentation Concrete tanks Sedimentation Channels
Drying Concrete floors Drying Plastic Paper Concrete floors Zinc
Packaging Paper Packaging Paper Polypropylene
Products:
Starch for human consumption Industrial starch (first grade) Industrial starch (second grade)
Figure 1. Differences in traditional and current technologies for cassava starch extraction, Manabí, Ecuador. Current technologies include innovations introduced from Colombia and Brazil.
and sedimentation in concrete Experiments channels lined with ceramic tiles. Drying is carried out naturally on Sour starch production trials were plastic sheets placed on bamboo first carried out in December 1992 platforms. When a finer quality and renewed in November 1993 at product is required, milling is two starch factories, both UATAPPY done in hammer mills (Figure 1). members. Artificial drying trials with
261 Cassava Flour and Starch: Progress in Research and Development a flash dryer will be conducted, elements of processing and together with mechanized sieving, technology. using vibrating or centrifuge screens.
Results Training and Institutional Support (1) Product quality (flours and starch) has improved, allowing new To introduce and adapt new cassava markets to be opened at national processing technologies, especially for and international levels. starch, UATAPPY received technical (2) Higher yields have been obtained and financial support from and efficiency has improved. FUNDAGRO and CIAT. Its technical (3) Production capacity, especially of team has received training nationally starch, has increased. and in Colombia and Brazil on
262 The Influence of Variety and Processing...
CHAPTER 30
THE INFLUENCE OF VARIETY AND PROCESSING ON THE PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF CASSAVA STARCH AND FLOUR
A. Fernández *, J. Wenham **, D. Dufour ***, and C. C. Wheatley†
Abstract This chapter outlines the results so far. The influence of certain processing conditions on the quality, functional Materials and Methods properties, and product potential of flour made from three cassava cultivars The cassava cultivars used in this are being evaluated as part of a research were selected after the project (DGXII) funded by the cassava core collection, held at CIAT, European Union (EU). The Cali, Colombia, was evaluated collaborators in this project are the (Wheatley et al., 1993). Cultivars were Universidad del Valle (UNIVALLE), selected to represent a broad Colombia; CIRAD-SAR, France; the variability in root contents of Natural Resources Institute (NRI), UK; cyanogens, dry matter, and amylose. and CIAT, Colombia. Experiments were designed to The influence of drying determine how flour preparation temperature (40, 60, and 80 °C), influences the resultant quality of the milling procedure (hammer, roller, pin, end product. In October 1992, and paddle), and particle size 1,500 kg of fresh roots of the cassava (< 250 µm and < 160 µm) on the cultivar CM 3306-4 were harvested at quality, functional properties, and CIAT. The roots were processed into product potential of flour from three flour as outlined: cassava cultivars are being evaluated. The influence of genetic variability on Fresh roots > Washing and peeling starch quality is also being evaluated, using starches made from cultivars Milling < Drying < Chipping < chosen from the cassava core collection > Sieving > Flour established at CIAT. In August and September 1993, two more cultivars of cassava * Universidad del Valle (UNIVALLE), Cali, (CM 3306-4, M Ven 25) were harvested Colombia. 10 months after planting and similarly ** Natural Resources Institute (NRI), Kent, UK. processed. *** CIRAD/SAR, stationed at the Cassava Utilization Section, CIAT, Cali, Colombia. † Centro Internacional de la Papa (CIP), Before drying, the chips from each stationed at Bogor, Indonesia. cultivars were divided into three lots of
263 Cassava Flour and Starch: Progress in Research and Development
475 kg. They were then dried in a including the same 29 cultivars, layer, about 15 cm thick, on the floor harvested at CIAT in July 1993 (3 m2 area) of an airflow bin dryer. 9 months after planting. Drying temperatures used were 40, 60, and 80 °C. The starch samples extracted from the cassava cultivars in 1992 were Four different types of mill were analyzed with a BA. Gelatinization used to grind the resultant dry chips: profiles were determined from (1) hammer mill (set at 5,800 rpm and 6%-starch solutions as described 1 with a 8 -inch screen), (2) roller mill above. The amylose contents were (first pass with rollers set at 300 µm determined, using an iodo-colometric apart and second pass with rollers set test and a calibration curve prepared at 30 µm), (3) pin mill, and (4) a from potato amylose and amylopectin. paddle auger in a cylindrical sifter The crystallinity of the starch granules with a 5-mm and 250-µm screen. The was determined with an X-ray flours produced were divided into two diffraction system. The diffraction sieve fractions to give two particle data were collected over an angular sizes: smaller than 250 µm, and range from 4° to 32° 20’. smaller than 106 µm. Starch samples from both harvests The flours produced by the will be examined for granular size different treatments were analyzed distribution,.amylose-to-amylopectin with a Brabender amylograph (BA). ratio, chain length, degree of Gelatinization profiles were polymerization, X-ray diffraction determined from 6%-starch solutions, patterns and absolute crystallinity, using a heating and cooling rate of differential scanning calorimetry (DSC) 1.5 °C/min. The temperature was analysis, pasting and rheological increased to 95 °C, held for characteristics, swelling power and 20 min, and cooled at a rate of solubility, and water-binding capacity. 1.5 °C/min to 50 °C. The viscographs obtained were used to calculate the following parameters: the initial Results temperature of gelatinization, peak viscosity, ease of cooking, gel Flour instability, and gelatinization index. The various processing procedures In October 1992, 29 cassava used in these experiments all cultivars were harvested at CIAT 10 influenced the gelatinization profiles to 12 months after planting. Starch of the resultant flours (Figures 1 to 4; samples were extracted as outlined: Table 1). Whether the differences obtained in gelatinization properties Fresh roots > Washing and peeling are enough to significantly influence the potential uses of the flours is yet to Starch removed < Rasping < be determined. At the time of writing, by adding water the flours prepared from the cultivars and filtering harvested and processed in August > Starch > Drying and September 1993 were not yet sedimentation analyzed.
Starch < Starch
Starch samples were also prepared Figure 5 shows a sample of the X-ray from another 33 cassava cultivars, diffractograms obtained from starches
264 The Influence of Variety and Processing...
350
300
250
200
150
100
50 Brabender viscosity units 0 0 2732374247525764748494 Time (minutes)
Figure 1. Viscoamylograph of cassava flour in relation to drying temperatures ( .. = 40 °C; = 60 °C; = 80 °C). Brabender curves were obtained from flour suspension at 6% of dry matter. The flour had a particle size smaller than 250 µm, after milling with rollers.
400
300
200
100 Brabender viscosity units 0 0 2732374247525764748494 Time (minutes)
Figure 2. Viscoamylograph of cassava flour in relation to drying temperatures ( .. = 40 °C; = 60 °C; = 80 °C). Brabender curves were obtained from flour suspension at 6% of dry matter. The flour had a particle size smaller than 250 µm, after milling with a hammer mill.
500
400
300
200
100 Brabender viscosity units 0 0 2732374247525764748494 Time (minutes)
Figure 3. Viscoamylograph of cassava flour in relation to particle size ( = 250 µm; = 106 µm). Brabender curves were obtained from flour suspension at 6% of dry matter. Chips were dried at 60 °C and milled in a hammer mill.
265 Cassava Flour and Starch: Progress in Research and Development
500
400
300
200
100 Brabender viscosity units 0 0 2732374247525764748494 Time (minutes)
Figure 4. Viscoamylograph of cassava flour in relation to milling method ( = hammer mill; ...... = pin mill; .. = roller mill; = paddle mill). The flour was made from chips dried at 60 °C, and flour particle size was smaller than 250 µm. Brabender curves were obtained from flour suspension at 6% of dry matter.
M Col 1132
M Col 72
M Col 22
M Bra 897
M Bra 881
M Bra 162
10 20 30 Angle (2-theta)
Figure 5. A sample of wide-angle, X-ray diffractograms of native starches from cassava cultivars harvested at CIAT, October 1992.
266 The Influence of Variety and Processing...
Table 1. Cassava flour functionality characteristics in relation to its particle size, the drying air temperature, and the milling procedure of the chips.
Flour characteristic Milling equipment and drying temperatures (°C)
Hammer Roller Pin Paddle
40 60 80 40 60 80 40 60 80 40 60 80
Flour composition:
Flour Aa: Starch (%, db) 83 82 79 85 83 81 84 82 81 88 86 82 Fiber (%, db) 0.9 0.8 1.0 1.4 1.0 1.6 1.2 0.7 1.3 1.0 1.2 1.3 Ash (%, db) 1.5 1.7 1.7 1.8 1.8 1.8 1.5 1.6 1.7 1.6 1.5 1.4
Flour Bb: Starch (%, db) 87 85 83 86 86 86 86 86 85 92 91 87 Fiber (%, db) 0.6 0.8 0.4 0.4 0.5 0.6 1.1 0.8 1.1 0.6 0.8 1.1 Ash (%, db) 1.4 1.5 1.5 1.7 1.3 1.6 1.5 1.5 1.7 1.5 1.3 1.5
Gelatinization temperature (°C):
Flour A 65.5 65.5 65.5 65.5 65.5 65.5 64.0 65.5 65.5 65.5 65.5 65.5 Flour B 65.5 65.5 65.5 65.5 65.5 65.5 65.5 64.0 65.5 65.5 65.5 65.5
Maximum viscosity:
Flour A 371 380 380 255 323 295 380 380 340 408 410 410 Flour B 385 420 380 285 350 327 387 405 360 400 430 425
Viscosity at 95 °C:
Flour A 365 365 366 251 321 289 377 363 340 390 380 385 Flour B 375 387 367 284 338 320 377 380 358 380 390 385
Viscosity after 20 min at 95 °C:
Flour A 172 175 185 102 152 131 202 183 239 168 180 190 Flour B 177 190 185 119 160 152 177 190 228 170 185 200
Viscosity at 50 °C after cooling:
Flour A 285 300 322 180 252 210 292 313 319 295 318 350 Flour B 308 327 320 180 285 260 297 340 335 305 340 380
Ease of cookingc:
Flour A 19 17 16 20 18 20 19 17 16 17 16 15 Flour B 18 16 16 20 17 16 18 17 15 17 16 14
Gel instabilityd:
Flour A 199 205 185 153 171 164 178 197 101 240 230 220 Flour B 208 230 195 166 190 175 210 215 132 230 245 225
Gelatinization indexe:
Flour A 113 125 137 78 100 79 90 130 80 127 138 160 Flour B 131 137 135 61 125 108 120 150 107 135 155 180 a. Flour A = flour with particles smaller than 250 µm. b. Flour B = flour with particles smaller than 106 µm. c. Ease of cooking = time to maximum viscosity - time to gelatinization. d. Gel instability = maximum viscosity - viscosity after 20 min at 95 °C. e. Gelatinization index = viscosity at 50 °C after cooling - viscosity after 20 min at 95 °C.
267 Cassava Flour and Starch: Progress in Research and Development
made from the roots of the October crystallinity and amylose content, 1992 harvest. All spectra of the 29 together with the analysis reported by cultivars analyzed showed an A-type, CIAT of root dry matter and cyanogen X-ray diffraction pattern. Table 2 gives contents. Table 3 gives the values calculated for starch gelatinization profiles of starch
Table 2. Dry matter of fresh roots, cyanogen content of fresh parenchyma, amylose content, and crystallinity of starch obtained from 29 cassava cultivars harvested at 10-12 months at CIAT, Palmira, Colombia, October 1992.
Cultivar Dry matter Total cyanogens Amylose Crystallinity (%) (as HCN, mg/kg, db) (% in starch) (%)a
M Bra 162 32 1,012 17 39 M Bra 881 31 832 20 41 M Bra 897 36 98 21 38 M Col 22 35 85 23 37 M Col 72 33 248 22 41 M Col 1132 21 69 26 39 M Col 1486 37 120 22 43 M Col 1684 37 752 23 38 M Col 2066 30 58 24 43 M Col 2215 43 243 25 44 M CR 35 45 17 24 41 M Mal 1 38 411 25 39 M Mal 2 27 413 24 40 M Mex 59 34 311 21 39 M Nga 2 22 632 23 47 M Per 196 33 393 21 42 M Tai 1 33 629 22 38 M Ven 25 27 1,628 22 43 M Ven 77 32 223 23 40 CG 1-37 35 182 22 44 CG 165-7 23 402 22 44 CG 402-11 18 169 20 45 CG 915-1 37 149 24 41 CG 1118-121 27 27 25 39 CG 1141-1 40 337 24 44 CM 489-1 23 86 41 CM 2766-5 32 82 43 CM 2772-3 27 114 42 CM 3306-4 39 82 43 a. Based on the separation and integration of the areas under the crystalline and amorphous X-ray diffraction peaks.
268 The Influence of Variety and Processing...
Table 3. Values of total cyanogen content in parenchyma, amylose content, starch crystallinity, and starch functionality characteristics for six cassava cultivars harvested in October 1992 at CIAT, Palmira, Colombia.
Characteristic Cultivar
CM 3306 CG 1-37 M Ven 77 CG 165-7 M Tai 1 M Ven 25
Total cyanogen in 82 182 223 402 629 1,628 parenchyma (as HCN, mg/kg, db)
Amylose (%) 26 22 23 22 22 22
Crystallinity (%) 43 44 40 44 43 43
Gelatinization 64.0 64.0 65.5 62.5 62.5 62.5 temperature (°C)
Maximum viscosity 975 775 610 800 780 730
Viscosity at 95 °C 415 320 330 350 340 310
Viscosity after 20 min 260 225 195 220 230 190 at 95 °C
Viscosity at 50 °C 520 460 380 435 410 330 after cooling
Ease of cookinga 4475 55
Gel instabilityb 715 550 415 580 550 540
Gelinization indexc 260 235 185 215 180 140
a. Ease of cooking = time to maximum viscosity - time to gelatinization. b. Gel instability = maximum viscosity - viscosity after 20 min at 95 °C. c. Gelatinization index = viscosity at 50 °C after cooling - viscosity after 20 min at 95 °C. samples analyzed. The results Reference obtained show a similar trend to that reported by Wheatley et al. (1993). Wheatley, C. C.; Orrego, J. I.; Sánchez, T.; Differences in starch viscosity and Granados, E. 1993. Quality characteristics were observed between evaluation of the cassava core cultivars with high and low cyanogenic collection at CIAT. In: Roca, W. M. content. and Thro, A. M. (eds.). Proceedings of the First International Scientific Meeting of the Cassava Biotechnology Research is continuing with the Network, Cartagena de Indias, 33 starch samples obtained from Colombia, 25-28 August 1992. cultivars harvested in July-August Working document no. 123. CIAT, 1993. Cali, Colombia. p. 255-264.
269 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 31
ESTABLISHING AND OPERATING A CASSAVA FLOUR PLANT ON THE ATLANTIC COAST OF COLOMBIA1
Francisco Figueroa*
Background price structures of cassava and wheat in Colombia, producing cassava flour CIAT has developed a strategy to at a price competitive with that of design and implement cassava wheat flour was economically feasible projects, integrating aspects of the (Tables 1, 2, and 3). Hence, the next crop’s production, processing, and phase, that of the pilot-project, was commercialization in northern initiated. Colombia. Within this framework, three phases of development can be In the research phase, baked distinguished: products had been considered as the main market, where cassava flour (1) Research: developing technology would substitute 15% of wheat flour. for cassava processing, and But, because bakers saw a high risk studying in detail the technology’s of decreased product quality when market opportunities, both on a using cassava flour, phase II was national and regional basis. focused on other food categories (2) Pilot project or market test: where cassava flour would not producing and marketing on a present high risks. small scale under real market conditions. With phase II, the production, (3) Commercialization or expansion: processing, and marketing consolidating the market for new components of the cassava flour products and replicating the system were integrated under the real processing units. conditions of a cassava-growing region in Colombia. These results A project to develop, under this can be used by both public and strategy, a rural cassava flour private enterprises to promote the industry was begun, and its progress replication of rural, cassava so far is reported here. flour-producing plants and the product’s use in the national food Results of phase I (research) industry. indicated that, under the cost and The institutions participating in the project are CIAT, Cali; * Fundación para la Investigación y el Universidad del Valle, Cali; the Fondo Desarrollo de Tecnologías Apropiadas al Agro (FUNDIAGRO), Colombia. de Desarrollo Rural Integrado (DRI) of the Colombian Ministry of 1. No abstract was provided by the author. Agriculture; and the Fundación para
270 Establishing and Operating a Cassava Flour Plant...
Table 1. Variable costs (US$) of cassava flour in January 1994, Chinú, Colombia.
Item Unit/t Unit cost Cost/t
Raw material 3.5 t 43.00 150.50 Labor 60 man-hours 0.40 24.00 Package 25 units 0.30 7.50 Electricity 140 kW/h 0.10 14.00 Mineral coal 550 kg 0.04 22.00 Water 7 m3 0.40 2.80 Variable costs 220.80
Table 2. Fixed costs (US$) of cassava flour, carried out by small-scale, rural Chinú, Colombia, January 1994. producers and inhabitants. It is implemented in three phases, and Item Cost/month Cost/t promotes cassava’s transformation in Managera 123.00 6.15 agroindustry by integrating functions Production chiefb 12.00 0.60 of production, processing, and commercialization. It is supported by Watchman 121.00 6.05 governmental and nongovernmental Maintenance 125.00 6.25 organizations. Other expenses 15.00 0.75 Fixed costs 396.00 19.80 Phase I of the Flour Project: a. The cost is shared by the chip and flour plants. Research (1985-1987) b. Bonus for production. Colombia’s economic situation, the prospects for cassava, and the Table 3. Production costs (US$) of flour in national potential for cassava-based Chinú, Colombia, January 1994. products were studied to select the most promising product and choose Item Cost/t an appropriate site. The Atlantic Variable costs 220.80 coastal region (northern Colombia) was also studied as having the Fixed costs 19.80 greatest potential for developing the Total production costs 240.60 project. Aspects such as cassava production, farmer organizations, and markets were taken into account to choose the best site for the pilot plant. la Investigación y el Desarrollo de Tecnologías Apropiadas al Agro Aim (FUNDIAGRO). The donor agency is the International Development The objective of this phase was to Research Centre (IDRC), Canada. determine the economic and technical conditions required for the project.
Methodology Used in the Activities Integrated Cassava Project Studies were made of the cassava The integrated cassava project is a production and marketing systems on rural development strategy. It is Colombia’s Atlantic coast. On-farm
271 Cassava Flour and Starch: Progress in Research and Development trials were conducted with compete with wheat flour in improved cassava production Colombia. technology. Economic studies were made of the wheat milling and baking industries. The Phase II: Pilot Project experimental cassava flour plant (1988-1992) was designed and developed. Trials were made of equipment A pilot plant was set up in Chinú, and processing. Laboratory trials Department of Córdoba (Figure 1), were made on flour quality and with technical conditions for consumer acceptance. semicommercial operation under real market conditions. Results Aims The results demonstrated the technical and economic feasibility The major objective was to validate of producing cassava flour to the technology under real field
Atlantic Ocean Barranquilla
Cartagena 120 km 220 km Sincelejo 30 km Panama Chinú 80 km Montería Venezuela
367 km Medellín
Pacific 258 km Ocean 473 km Santafé de Bogotá
Cali
Ecuador
Brazil Peru
Figure 1. Site for the cassava-flour production pilot plant in northern Colombia. The pilot plant is part of phase II of a project to develop new, market-oriented, cassava-based products and their markets.
272 Establishing and Operating a Cassava Flour Plant... conditions, integrating production, were contacted, and test trials processing, and marketing. Other conducted with them. objectives were to (1) gather reliable Commercializing cassava flour in the data on production costs and on the meat processing and adhesive investment needed to establish this industries began. type of plant; (2) produce enough cassava flour to promote its use At the time of writing, project among consumers; and (3) use the expansion to other areas of Colombia plant as a display model to expand had not yet started, market this technology to other regions of expansion was still to come, together Colombia. with a further consolidation of the new rural agroindustry. Activities Aim The main activity was to establish the pilot plant. Criteria for site The objective was to market cassava selection included aspects of flour and consolidate a rural cassava production, land agroindustry that would benefit availability, potential for increasing farmers, not only in northern cassava yields, processing, raw Colombia, but also in other regions. material availability (production, seasonality, access to fresh market), Activities service infrastructure (water, electricity, roads), proximity to A marketing plan was designed and terminal markets, institutional executed, and market segments presence and support, potential selected. A bibliographical review project impact, and socioeconomic was made of cassava flour uses. importance of cassava. Commercial contacts were established and sales volume and Alternative sites were surveyed, conditions determined. four potential zones selected, then a site, with farmer organizations close Results by, was chosen. The pilot plant was redesigned, in which combined Commercialization of cassava flour natural and artificial drying was has begun. The model has been eliminated. A designer and builder evaluated and adjusted and new were contracted and the redesigned sites selected. The project is plant built. expanding to other zones.
Results A Cooperative Carries Out The pilot plant began operating the Project with adjustments in production, processing, and marketing. A The Cooperativa de Productores de viable and functional model was los Algarrobos (COOPROALGA), obtained. based in Chinú, is a first-order organization with 43 members, all small-scale farmers dedicated to Phase III: Commercial growing cassava intercropped with Expansion (1993 Onward) maize or yam. Most members pay rent for land and the remaining 20% A market study for the new product own it. was designed and developed, clients
273 Cassava Flour and Starch: Progress in Research and Development
COOPROALGA manages two Universidad del Valle and CIAT plants, one producing cassava chips designed the main processing for animal feed, and the other the equipment, which was built in Cali. pilot cassava flour plant (Figure 2). Processing
Characteristics of the Plant, A batch process was implemented Process, and Product and includes the following operations: harvest, transport, The flour plant reception, weighing, selecting, preparing, washing, chipping, The cassava flour plant is a drying, premilling, and milling. The warehouse with an office, bathrooms, resulting cassava flour is then a tool room, a coal storage room, and packaged and stored (Table 4 and areas where cassava roots are Figure 3). received, washed, chipped, and dried. The ground area of the plant is Each batch is processed in 2,058 m2. 2 days. On the first day, the roots are harvested, transported, selected, The plant has two water storage and prepared. On the second day, tanks, one underground with a they are washed, chipped, dried, and capacity of 39 m3 and the other milled, and the resulting flour elevated, holding 6 m3. All the plant’s stored. residual waters flow in two independent lines. The plant’s walls The product are of concrete blocks, and the roof has a metal framework and is tiled Before harvesting, the farmer prunes with asbestos. the cassava plant, removing aerial parts, and on the next day he Construction of the plant had cost harvests and packs the roots, and US$29,484.00 in March 1990. The takes them to the plant.
Second-order organization
Other cooperatives COOPROALGA
Accountant Manager Head of Marketing
Treasurer Production chief Coordinator for purchases
Workers (4), Watchman (1)
Figure 2. The organization of the pilot cassava flour plant set up in Chinú, northern Colombia.
274 Establishing and Operating a Cassava Flour Plant...
Table 4. Processing 1 t of cassava flour in a pilot plant, Chinú, northern Colombia.
Day Hours Activity Man-hours (no.) Workers (no.)
1 5:00 - 11:00 Harvest (3.5 t) - - 9:00 - 14:00 Root transportation - - 9:00 - 14:00 Reception and weighing 2 1 14:00 - 18:00 Selection and preparation 20 5
2 7:00 - 11:00 Washing and chipping 8 2 7:00 - 11:00 Loading the drying chamber 4 1 6:00 - 7:00 Cleaning the burners 1 1 7:00 - 8:00 Drying starts 1 1 8:00 - 20:00 Drying (chip turning) 20 3
3 6:00 - 7:00 Cleaning and maintenance 2 2 6:00 - 7:00 Unloading the dryer 1 2 7:00 - 8:00 Milling and packaging 1 2
Total 60 6
Figure 3. Procedures in cassava flour processing at the pilot plant, Chinú, northern Colombia. (Dotted lines refer to secondary processes.)
Cassava roots are received in 50 After washing, chipping, drying, to 60 kg sacks, and should have been milling, and sieving through 150 harvested on the day of receipt. They microscreens, cassava flour is finally should also be free of diseases, obtained. deterioration, or severe mechanical damage, and should be from varieties containing high dry matter content.
275 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 32
IMPROVING PROCESSING TECHNOLOGIES FOR HIGH-QUALITY CASSAVA FLOUR
D. M. Jones*, D. S. Trim*, and C. C. Wheatley**
Abstract limited scope for other crops, because of harsh climate, poor soils, or both. The potential of cassava flour to Markets for fresh roots for direct diversify markets for cassava consumption are stagnant or producers is investigated. The effects diminishing in many places because of different root processing regimes on of increasing urbanization and cyanogen contents and microbiological changes in eating habits. Demand for counts—major factors governing roots for starch and chips for animal quality in cassava flour—were feed, although existing where such investigated at CIAT. Chipping, industries operate, is limited. Cassava rasping, and different drying flour is a product that could help technologies were evaluated in terms diversify and strengthen cassava of product quality. Three types of markets for these small producers. chippers, five raspers, and drying by sun, oven, or bin were used. Rasping The main industrial market and drying reduced the cyanogenic opportunities for cassava flour are in glucoside contents of the roots by 90% the substitution of other raw to 100%, but microbiological counts materials, primarily wheat flour or were high for all drying technologies. starches, for further processing into The chipping trials indicate that sun final products. In some areas, smaller drying on trays produced chips of regional markets exist for local, similar microbiological quality to cassava-based food specialties. To artificial drying. penetrate these markets, cassava flour must be of at least comparable quality to the product it is potentially Introduction replacing. Possible clients are unlikely to risk changing feed stocks if it is at Cassava is grown in many parts of all possible that the quality of their the developing world, mainly by end product will be adversely affected. small-scale farmers, for both food and income. Often such farmers have Factors of Flour Quality
Microbiological quality
Wheat flour tends to be of high * Natural Resources Institute (NRI), Kent, UK. ** Centro Internacional de la Papa (CIP), microbiological quality, because the stationed at Bogor, Indonesia. economic product (the grain) develops
276 Improving Processing Technologies for High-Quality Cassava Flour above the ground; is cultivated with glucosides (CG), cyanohydrins, and modern, large-scale, farming practices; hydrogen cyanide (HCN). The and is harvested at relatively low glucosides initially present in the moisture content. In contrast, cassava fresh roots are broken down, during roots are usually cultivated with basic processing, to the other cyanogens farming practices, picking up a given above (Bokanga, 1992). microbial load from the soil, and have Cyanogen concentrations are a much higher moisture content than expressed as mg HCN equivalent per grains. Hence, cassava flour is likely kg of dry matter, unless otherwise to have higher levels of microbiological stated. Nonglucosidic cyanogen (NGC) growth. concentration describes the combined concentrations of cyanohydrins and Table 1 gives selected flour HCN. The cyanogen levels remaining standards. The Colombian standard vary with the raw material permits the same maximum bacterial concentration and the processing loads for both wheat and cassava technologies employed (Fish and Trim, flours. Cassava flour has a lower 1993). These levels are not a major maximum permitted moisture than concern for nonfood use. wheat flour, because of its perceived greater susceptibility to contamination. Hydrogen cyanide is toxic, but is usually present only in small Cyanogens quantities because of its volatility. Evidence suggests that cyanide Cassava flour also contains residual poisoning and intoxication resulting levels of cyanogenic compounds from consumption of cassava flour (cyanogens), mostly cyanogenic may be caused by high residual
Table 1. Quality standards for selected flours.
Quality criterion Cassava flour Wheat flour
Colombiana Africanb Colombianc Tanzaniand
Chemical composition (maximum permitted levels):
Moisture (%) 120 130 1400 Starch (% minimum) 620 Ash (%) 20 30 0.700 Crude fiber (%) 2.50 20 200 Sand (%) 30 100 Crude cellulose (%) 50 Total HCN (mg/kg) 500
Microbial content (cfu/g):
Aflatoxins 00 Aerobic plate count at 35 °C 2 x 105 2 x 105 1 x 105 Coliform bacteria 1 x 102 1 x 102 Escherichia coli 00 00 00 Salmonella 00 00 00 Molds and yeasts 1 x 103 1 x 103 1 x 103 a. ICONTEC, 1990. b. FAO and WHO, 1992. c. ICONTEC, 1967. d. Tanzania Bureau of Standards, 1989.
277 Cassava Flour and Starch: Progress in Research and Development cyanohydrin levels, which then the standard, and would increase decompose after ingestion (Banea, the range of varieties that the 1993; Mlingi et al., 1992). The effect plant’s processing operations can of consuming CG on health is less satisfactorily detoxify. Manually clear and has not yet been peeling the roots was not thoroughly investigated. investigated at this stage. (2) To investigate means of processing Few official standards exist high cyanide varieties of cassava specifically for cassava chips and into flour with safe residual flour for human consumption. The cyanogen levels. Colombian standard for dried High cyanogen varieties are more cassava sets a maximum total suited to some agroecological cyanogen content of 50 mg/kg (fresh zones, and are preferred to low basis), measured as HCN (ICONTEC, cyanogen varieties in some 1990). The regional standard being regions. The operations of developed for Africa (FAO and WHO, chipping and drying do not 1992) sets a maximum total eliminate enough cyanogens to cyanogen content of 10 mg/kg (fresh process high cyanogen varieties basis). The standards are expected satisfactorily. to evolve with the product, and further guidance may be found in the proceedings of the Cassava Effect of Chip Size on Safety Workshop held in 1994. Residual Cyanogens in Bin-dried Chips
Research on Processing Methods Technologies Trials were carried out with three The quality of the cassava flour different chipping disks: the produced at the CIAT pilot plant was standard disk (CIAT-designed); a rigorously evaluated in terms of modified version with reduced chip residual cyanogens and aperture to give thinner chips; and a microbiological quality (results not grating disk designed by the Ecole shown). Research was then carried nationale supérieure des industries out at CIAT, with the following agricoles et alimentaires (ENSIA), objectives: France (Monroy-Rivera, 1990). Roots 11 months old were harvested the day (1) To investigate the modification of before the trial and stored outdoors chip size as a means of overnight (normal factory plant increasing the elimination of practice). The roots were washed in a total cyanogenic potential (CNP) drum washer, which also effectively during flour production. dehusks the roots, and chipped. The The degree of cyanogen wet chips were bin-dried at 60 °C, at elimination achieved by the pilot loading densities of 75 and 85 kg/m2 plant effectively sets the (Figure 1). Six samples were taken maximum initial cyanogen from both fresh and dried chips, and concentration in the feed roots analyzed with the modified Cooke acceptable by a plant of this method (O’Brien et al., 1991). type. Increasing the elimination of cyanogens without Results fundamentally changing the process would ensure that the Table 2 gives the cyanogen contents cassava flour produced meets measured during these trials.
278 Improving Processing Technologies for High-Quality Cassava Flour
Fresh roots
Washer 30 L/min for 5 min
Standard Modified chipping Grating chipping disc disc disc
Bin dryer Bin dryer 75 kg/m2 85 kg/m2 60 °C 60 °C Air flow: Air flow: 0.5 kg/s.m2 0.5 kg/s.m2
Figure 1. Procedures used in cassava-chipping trials.
Standard disk. The total CNP shorter period, and earlier in the fresh chips were reduced by termination of cyanogenic reactions. about 34% by chipping with the standard disk, followed by drying The low degree of elimination within 5 hours. This figure is obtained with the modified chips consistent with the results obtained indicates that the effect of fast by using the same disk at the pilot drying is masking any effect of plant, where proportionally greater chipping, which would be more reductions in CNP were achieved obvious at the slower drying rates with longer drying times. This was obtained at higher loading densities. despite processing a different variety under different climatic conditions. Grating disk. The grating disk showed a higher reduction (56%) Modified disk. The modified than the standard chipper (34%) of disk achieved a similar level of CNP, with chipping and drying. reduction in CG, but with a lower This is consistent with the greater overall CNP reduction of 28%. extent of tissue damage achieved. Reduction of CG with chipping and The modified chips had an drying was consistent at 59%-61%. average thickness of 4.3 mm, The reduction in CG is dictated by compared with 6.1 mm for the the quantity of glucosides brought normal chips, providing a greater into contact with linamarase cut-surface area. A greater initial enzyme, which, in turn, depends on elimination of the CG was therefore the extent of tissue damage. expected in the modified fresh chips Cyanogenic glucosides in because of the higher percentage of undamaged tissue remain intact. damaged root tissue. Under The chips produced by the grating suitable conditions, a faster drying disk were more fragile than the pilot rate was also expected, leading to plant ones and less suitable for bin surface drying of the chips in a drying.
279 Cassava Flour and Starch: Progress in Research and Development
):
2
(kg/m
59 57 61
29 54
2
85 kg/m
Modified disk at
loading density of
.
b
):
2
(kg/m
39 32 35 28
85 75 85 75
CNP NGC CG CNP NGC CG CNP NGC CG CNP NGC CG CNP NGC CG
measured during cassava chipping trials
a
Table 2.concentrations Cyanogen
Fresh chips(%)drying and chipping with Reduction 36 1,269 253 1,016 1,096 172 924 832 152 680 858 320 539 1,118 198 920 (mg HCN equiv./kg dry matter) a. CNP = total cyanogen potential; NGC = nonglucosidic cyanogen content; CG = cyanogenic glucoside content. Dried chipsDried b. roots of M Ven 25, a high cyanogen variety. Each value is an average of six samples; percentage of reduction in both CNP and CG is based on fresh chips CNP; all trials used 812 35 776 746 38 709 598 7 591 396 40 356 480 41 439 (mg HCN equiv./kg dry matter)
Reduction with chipping (%) 20 16 18 37 18
Cyanogenic contentsCyanogenic Standard disk at loading densitydensity loading at disk Grating
280 Improving Processing Technologies for High-Quality Cassava Flour
Summary (5) A plastic, Jahn rasper (experimental), in which metal Elimination of CNP from chips made serrated blades are mounted by the standard disk increased with laterally on a plastic drum. drying time, regardless of cassava variety or location. Four of the rasper drums tested were interchangeable within the The grating disk eliminated 22% same rasper frame, designed to more CNP than the pilot plant disk at investigate their relative starch the same loading density. Grated extraction efficiency. The drums chips, however, are more fragile than were 400 mm in length and 270 mm standard chips and less suitable for in diameter. The plastic Jahn rasper bin drying. drum was a smaller, self-contained unit, 275 mm in length and 200 mm in diameter. An ordinary 5-HP motor Effect of Different Raspers was used for all the raspers. The on Residual CNP in wooden Jahn rasper and the Tray-Dried Pulps punched-drum rasper are in common use in the cassava starch industry. The effect of different raspers on the degree of cyanogen elimination Roots were harvested at achieved with rasping and drying was 9 months and stored as for the investigated. Rasping almost chipping trials. The roots were completely destroys the root tissue washed in clean but untreated water structure, much more so than and dehusked manually. Fifteen chipping. The trials used roots of kilograms of the washed roots were M Ven 25, a very high cyanogen rasped without adding water. The variety, to establish the upper limits resulting pulp was mixed and of cyanogen elimination. dried at 8 kg/m2 on two trays in a despatch tray dryer at Methods 60 °C (Figure 2). Four samples each of the fresh and dried pulps were Five different raspers were used: taken for evaluation of cyanogen concentrations. This procedure was (1) A conventional, wooden Jahn followed for each rasper. rasper, in which serrated blades are mounted laterally on a wooden Results drum. (2) A punched-drum rasper, Table 3 gives the cyanogen consisting of a metal sheet with concentrations measured during this outward facing jagged holes trial. (punched through with a nail), fixed around a wooden drum Cyanogen contents of rasped frame. pulps. The reduction in CG with (3) A pin rasper (experimental), a rasping only was variable, with both metal drum scored diagonally in the Jahn raspers reducing the CG by both directions across its length 65%, and the punched drum by 43%. with metal pins protruding about When the pulps were both rasped 5 mm from the drum’s surface. and dried, the CNPs were reduced (4) An abrasion rasper (experimental), by 94%-96% for all raspers, with a layer of carborundum, regardless of the degree of reduction about 10 mm deep, fixed around a effected by rasping alone. The drum. residual CNPs in the pulps ranged
281 Cassava Flour and Starch: Progress in Research and Development
95 96
rasping and drying (%)
(%)
69
Reduction of
CG with rasping
.
b
during cassava-rasping trials, measured in mg CN equiv./kg dry matter
a
N/A 2,234 293 1,941 2,045 1,358 687 111 25 87
(kg/min)
Rasper drumroots Fresh pulp Fresh pulp Dried with Reduction
M Ven 25, a high cyanogen variety.
Table 3. Cyanogen concentrations Type Feed CNP NGC CG CNP NGC CG CNP NGC CG CNP CG
Wooden JahnWooden 28.6 2,318 271 2,047 2,195 1,409 786 104 29 74 66 96 97 Punched drumPunched 32.6 2,417 243 2,175 2,267 968 1,299 152 88 64 46 94 97 Abrasion 2.1 2,024 235 1,789 1,932 1,372 559 132 29 103 72 94 95 Metal pinMetal 15.0 2,608 315 2,293 2,236 881 1,355 163 27 137 48 94 95 Plastic Jahn Plastic
a. CNP = total cyanogenic potential; NGC = nonglucosidic cyanogen content; CG = cyanogenic glucoside content. b. based on fresh root CNP; all trials used roots of Each value is an average of six samples of fresh roots and four samples of pulp; percentage of reduction in both CNP and CG is
282 Improving Processing Technologies for High-Quality Cassava Flour
Fresh roots
Manual washing
Wooden Jahn Punched-drum Abrasion Metal Plastic Jahn rasper rasper rasper pin rasper rasper
Tray dryer 8 kg/m2 60 °C
Figure 2. Procedures used in cassava-rasping trials.
from 104 to 163 mg/kg. In previous reduction in CNP achieved with the milling trials, the residual CNP abrasion rasper was not significantly concentration in first-grade flour was different to that achieved with the about 36% of the level in freshly dried other raspers. The pulp was also more chips. Assuming this to hold true for liquid and difficult to handle than the pulps, the flours would have CNPs others. between 38 and 58 mg/kg, thus mostly meeting the Colombian Summary standard of 50 mg/kg. Except for the abrasion rasper, the This level of total cyanogen raspers evaluated were suitable for elimination probably approaches the processing roots with high cyanogen maximum possible in practice, given contents to flour with low cyanogen that variations occur because of content. The wooden Jahn and the fluctuating conditions. No significant punched-drum raspers are differences in the overall elimination of commercially available. CNPs was found between the raspers.
Root throughput. The abrasion Effect of Different Drying rasper’s root feed was 10% below that Techniques on Residual of the Jahn or punched-drum raspers, Cyanogens and the thus making it unsuitable for Microbiological Quality of commercial flour production. The Dried Pulps and Chips shredding action employed by both the Jahn and punched-drum raspers The effects of different drying removes a deeper layer of root tissue techniques (sun and artificial) on the with each contact than does the microbiological quality and on the erosive action of the abrasion rasper, cyanogen concentrations of chips and resulting in a larger root feed. rasped pulps were evaluated.
The pulp produced by the Rasped pulp is not suitable for bin abrasion rasper was finer and more drying, and the effect of rasping on the homogenous than the other pulps, microbiological quality of the dried indicating a greater degree of tissue product is unknown. Because smaller comminution. However, the final operations may not be able to justify
283 Cassava Flour and Starch: Progress in Research and Development the investment and cost of artificial sun, and in an oven at 60 °C. The drying, the effect of sun drying on the final trial was carried out with the microbiological quality of products was modified chipper, with the chips dried also evaluated. at 5 kg/m2 in the same way (Figure 3). Chips were also bin-dried at 70 kg/m2 Methods and 60 °C (Figure 4). The chips and pulps were mixed manually every Three trials were carried out on 2 h during drying. Three composite 10-month-old roots of cassava variety samples of each dried product were M Ven 25. The first two trials used the taken for microbiological analysis. wooden Jahn and punched-drum The samples were analyzed for aerobic raspers for root comminution. The plate counts (APC) (35 °C), spore roots were washed and dry-rasped as counts (35 °C), and yeasts and molds in the rasping trials described above. the following day (ICMSF, 1978). Four The pulps were dried at loading samples each of the fresh and dried densities of 5 and 10 kg/m2 on raised pulps were also taken for cyanogen trays and on a concrete floor in the evaluation.
Fresh roots
Washer 30 L/min for 5 min
Wooden Jahn Punched-drum rasper rasper
Oven Oven Sun Sun Sun Sun 60 °C 60 °C Raised tray Raised tray Concrete floor Concrete floor 5 kg/m2 10 kg/m2 5 kg/m2 10 kg/m2 5 kg/m2 10 kg/m2
Figure 3. Procedures used in cassava rasping and drying trials.
Fresh roots
Washer 30 L/min for 5 min
Modified chipper
Oven Bin Sun Sun 60 °C 60 °C Raised tray Concrete floor 5 kg/m2 70 kg/m2 5 kg/m2 5 kg/m2
Figure 4. Procedures used in cassava chipping and drying trials.
284 Improving Processing Technologies for High-Quality Cassava Flour
Results drop with storage and may also be reduced by the heat generated by Table 4 gives the cyanogen milling to flour. concentrations measured during the trials and Table 5, the microbiological Microbiological quality of dry counts. pulps and chips. All of the dried, rasped, pulp samples had high APCs Cyanogenic contents of dried (108 cfu/g), as did the chips which chips and pulps. Compared with were sun dried on a concrete floor. the rasping-only trials, the punched The oven-dried, and raised-tray, drum reduced CG (88%) more than sun-dried chips were of acceptable the wooden Jahn rasper (53%). quality (105 cfu/g), and the bin-dried Rasping and drying reduced the CG chips had only slightly higher by 90%-100%. Sun-dried pulps counts. The rasped pulps provide a tended to have higher residual NGC better substrate for microbial growth than did oven-dried pulps, possibly than the chips, as the cell contents because of the higher rate of removal (e.g., sugars and proteins) have all of HCN during forced-circulation oven been released by rasping. drying, which would increase the rate of breakdown of cyanohydrin to HCN. However, the APCs of fresh chips Residual cyanohydrin levels tend to have been measured at around
Table 4. Cyanogen concentrationsa during drying trials (rasped pulp only), measured in mg CN equiv./kg dry matterb.
Cyanide Pulp sample from: concentration Wooden Jahn rasper Punched-drum rasper
CNP NGC CG Reduction with CNP NGC CG Reduction with rasping and rasping and drying (%) drying (%)
CNP CG CNP CG
Fresh pulp 1,302 696 606 54 1,562 1,383 179 87
Dried pulp:
Oven, 5 kg/m2, 154 30 124 88 91 37 17 20 98 99 60 °C
Oven, 10 kg/m2, 105 31 74 92 94 33 28 5 98 >99 60 °C
Sun, 5 kg/m2, 99 47 52 92 96 53 45 7 97 >99 raised tray
Sun, 10 kg/m2, raised tray 67 51 15 95 99 60 50 9 96 99
Sun, 5 kg/m2, concrete floor 84 77 8 94 99 68 61 7 96 >99
Sun, 10 kg/m2, concrete floor 85 82 3 95 >99 81 73 8 95 99 a. CNP = total cyanogenic potential; NGC = nonglucosidic cyanogen content; CG = cyanogenic glucoside content. b. Each value is an average of six samples of fresh roots and four samples of pulp; percentage of reduction in both CNP and CG is based on fresh pulp CNP; all trials used roots of M Ven 25, a high cyanogen variety.
285 Cassava Flour and Starch: Progress in Research and Development
Table 5. Microbiological quality of dried pulp and chips generated in cassava-drying trials.
Rasping and drying Loading density Microbiological counta method (kg/m2) Aerobic Spore count Yeast and mold plate count at 35 °C count at 35 °C
Wooden Jahn rasper: Oven, 60 °C 5 3.43 x 108 3.18 x 105 4.99 x 104 Oven, 60 °C 10 3.58 x 108 2.61 x 105 5.40 x 104 Sun, raised tray 5 4.57 x 108 6.63 x 104 8.18 x 104 Sun, raised tray 10 2.95 x 108 3.10 x 104 5.64 x 104 Sun, floor 5 5.64 x 108 9.20 x 104 1.03 x 105 Sun, floor 10 3.51 x 108 3.28 x 104 3.08 x 104
Punched-drum rasper: Oven, 60 °C 5 1.01 x 108 8.02 x 104 6.33 x 103 Oven, 60 °C 10 2.12 x 108 3.74 x 104 2.65 x 104 Sun, raised tray 5 2.08 x 108 2.84 x 104 5.48 x 104 Sun, raised tray 10 5.24 x 108 1.92 x 104 1.97 x 105 Sun, floor 5 1.13 x 108 1.38 x 104 1.15 x 105 Sun, floor 10 5.93 x 108 1.87 x 104 7.13 x 104
Modified chipper: Oven, 60 °C 5 5.45 x 105 4.50 x 102 2.67 x 102 Bin, 60 °C 70 2.04 x 106 8.67 x 102 7.33 x 102 Sun, raised tray 5 2.18 x 105 3.33 x 102 1.33 x 102 Sun, floor 5 4.01 x 108 1.71 x 105 2.15 x 105 a. Counts expressed as colony forming units per gram (cfu/g), wet weight basis; average of three composite samples.
105 cfu/g (Table 6). Previous Summary pilot-plant experience has shown that, with long drying times (22 h), Rasping and drying of cassava roots the APCs of the chips are at is an effective means of reducing the 108 cfu/g, but reducing the drying CNP present in high cyanogen cassava time to 10 h reduces the APCs to varieties. However, the greater degree 105 cfu/g. Faster drying of the pulp of root disintegration leads to may therefore offer a means of increased microbiological growth. reducing the counts. The shortest pulp drying time of 6 h was insufficient to affect the counts. Conclusions
Raised-tray sun drying of chips Processing with the grating disk gave a product of good reduced CNP by 22% more than the microbiological quality with APCs standard disk. However, drying grated similar to those of oven-dried chips. chips at high loading densities may be Thus, this method may have difficult. potential for reducing costs under suitable climatic conditions (site Fast drying stopped the specific). elimination of cyanogens early in the
286 Improving Processing Technologies for High-Quality Cassava Flour
Table 6. Microbiological quality of processed samples from pilot plant and CIAT trials, November 1991.
Sample Microbiological countsa
Aerobic plate Spore count Coliforms Fecal coli-forms count at 35 °C at 35 °C (MPNb) (MPNb)
CIAT: Soil 7.7 x 107 8.1 x 105 >1.1 x 103 15 Root peelc 3.0 x 107 6.2 x 104 >1.1 x 103 <3 Parenchyma 1.2 x 103 1.5 x 102 <3 <3
Pilot plant: Soil 6.8 x 107 5.7 x 107 >1.1 x 103 40 Root peelc 1.4 x 107 3.0 x 105 >1.1 x 103 7 Well water 4.6 x 103 8.3 x 101 <3 <3 Tank waterd 4.7 x 103 2.6 x 102 <3 <3 Fresh chips 4.9 x 105 2.8 x 103 1.1 x 103 500 a. Counts expressed as cfu/g (wet weight basis) for processed samples and as cfu/ml for water samples. b. MPN = most probable number. c. Root peel includes bark and peel. d. Tank water treated with 10-20 mg/L free chlorine.
SOURCE: D. S. Trim and P. Wareing, 1991, personal communication.
drying period of the modified-disk Bokanga, M. 1992. Mechanisms of the chips, masking any effect chip size elimination of cyanogens from cassava might have had. Greater reduction during traditional processing. In: Westby, A. and Reilly, P. J. A. (eds.). Proceedings in CNP is likely at higher loading of a Regional Workshop on Traditional densities. African Foods - Quality and Nutrition, 25-29 Nov. 1991, Dar es Salaam. Rasping and drying is an International Foundation for Science effective means of processing even (IFS), Uppsala, Sweden. p. 157-162. very high cyanogen roots to a flour FAO and WHO (Food and Agriculture that meets the Colombian standard. Organization of the United Nations and Further work is needed to improve World Health Organization), Codex the product’s microbiological Alimentarius Commission. 1992. Codex quality. standard for edible cassava flour— African regional standard— CODEX STAN 176-1991. Eighth session In suitable climatic conditions, of the Codex Committee on Cereals, raised-tray sun drying of chips gives Pulses and Legumes, CX/CPL 92/9, a product of good microbiological June, 1992. FAO/WHO Food Standards quality. Program, Rome, Italy. 17 p.
Fish, D. M. and Trim, D. S. 1993. A review of research into the drying of cassava References chips. Trop. Sci. 33:191-208.
Banea, M. 1993. Cassava processing, ICMSF (International Commission on dietary cyanide exposure and konzo Microbiological Specifications for in Zaire. Thesis for Master of Foods). 1978. Microorganisms in foods, Medical Sciences degree. 1: their significance and methods of International Child Health Unit enumeration. 2nd ed. Academic Press, (ICH), Uppsala, Sweden. 65 p. London, UK.
287 Cassava Flour and Starch: Progress in Research and Development
ICONTEC (Instituto Colombiano de Normas Monroy-Rivera, J. A. 1990. Eliminación de Técnicas). 1967. Harina de trigo para compuestos cianogénicos durante el panificación. In: Industrias secado de yuca. Informe de los alimentarias, 2nd rev., vol. 10. trabajos realizados en el CIAT. Ecole NTC 267. Bogotá, Colombia. p. 55-67. nationale supérieure des industries agricoles et alimentaires (ENSIA), ______. 1990. Yuca seca para consumo Massy, France. 51 p. humano. In: Frutas, legumbres y hortalizas. NTC 2716. Bogotá, O’Brien, G. M.; Taylor, A. J.; and Poulter, Colombia. N. H. 1991. Improved enzymic assay for cyanogens in fresh and processed Mlingi, N. L. V.; Assey, V. D.; Poulter, N. H.; cassava. J. Sci. Food Agric. and Rosling, H. 1992. Cyanohydrins 56:277-289. from insuffiçiently processed cassava induces ‘KONZO’, a newly identified Tanzania Bureau of Standards. 1989. paralytic disease in man. In: Westby, Tanzania wheat flour specification. A. and Reilly, P. J. A. (eds.). TZS 439:1989. Dar es Salaam, Proceedings of a Regional Workshop Tanzania. on Traditional African Foods - Quality and Nutrition, 25-29 Nov. 1991, Dar es Salaam. International Foundation for Science (IFS), Uppsala, Sweden. p. 163-169.
288 Cassava Flour in Malawi: Processing, Quality, and Uses
CHAPTER 33
CASSAVA FLOUR IN MALAWI: PROCESSING, QUALITY, AND USES
J. D. Kalenga Saka*
Abstract Introduction
The quality of flour processed from Cassava (Manihot esculenta Crantz) is cassava (Manihot esculenta Crantz) by a major root crop in the tropics, and two methods commonly used in its starchy roots are a significant Malawi was determined. The first, source of calories for more than simple sun-drying, gives a flour 500 million people worldwide (Cock, known as ntandaza; the other— 1985). In Malawi, cassava is the soaking in water, followed by sun second most important staple after drying—provides kondowole flour. maize (DEPD, 1987): about 30% of Processing affects both the nutritional the population depends on cassava quality and cyanogen content of the for calories (Sauti, 1982). The crop final products. The soaking step grows easily in all parts of the significantly reduces mineral and country, but especially along the protein contents and raises the shores of Lake Malawi where it is the carbohydrate level (P > 0.05) to most important staple food. Since the 91.1% ± 1.1% for ntandaza flour and 1991/92 drought, which devastated 95.3% ± 0.7% for kondowole. Malawi, the Government has intensified the country’s production of The soaking step, followed by sun cassava, a drought-resistant crop, to drying, reduces the cyanogen content guarantee food security. more than sun drying alone. In soaking + sun drying, less than 10 mg Cassava is eaten in various HCN/kg dry wt were detected in the forms; these determine the methods final products, representing a of processing, which aim to 98.0% ± 1.6% reduction of initial (1) provide products that are cyanogen content. Simple sun drying storable and easy to transport to reduced total cyanogen content by market; (2) improve the taste of final 82.9% ± 5.2%. products; (3) reduce potential cassava toxicity; and (4) provide The uses of cassava flour in products such as flour for bakery, brewing, and making cassava subsequent conversion to a variety sima are described. of end products (Hahn, 1989; Lancaster et al., 1982). In Malawi, two methods are employed to make cassava flour, resulting in two kinds * Chemistry Department, Chancellor College, of flour: kondowole and ntandaza University of Malawi, Zomba, Malawi. (Saka, n.d.; Williamson, 1975).
289 Cassava Flour and Starch: Progress in Research and Development
Kondowole flour is prepared by cassava-based products improves soaking peeled cassava roots for 2 to (Sauti et al., 1989). 7 days; sun drying the soft mass (called maphumu) and pounding the Ntandaza flour is made by sun dried mass to make the flour drying peeled and/or partially peeled (Figure 1). This product is popular roots for 1 week or several months. among lakeshore populations living in The roots may be dried whole, as cut Karonga District to as far south as pieces, or after pounding; the last Nkhotakota District (Figure 2). The dries fastest. The dried product is soaking of unpeeled roots is also called makaka and the resultant flour practiced, but the flour gives products is commonly known as ntandaza. which taste bitter and appear darker. The flour is also referred to as The flour is used in its pure form or is ntandasha and mtandasha, mixed with cereal flours (maize, depending on the locality. sorghum, millet, wheat, or rice). This method of processing Among other things, the flour is cassava is predominant in central and used to make sima. Its preparation southern Malawi (Figures 2 and 3). A involves adding the flour to variation of the methodology involves simmering water and stirring the first covering the cassava roots with paste to consistency. Both pure and banana leaves to induce mold composite flours are used for brewing formation. The moldy product is then sweet and alcoholic beverages. When sun dried to provide a darker and mixed with wheat flour, the composite moldy makaka (Van Drongelen, flour is widely used to bake breads, 1992). scones, cakes, and biscuits. The pure kondowole flour is also used in Although the ntandaza flour is baking. When mixed with cereal used in the same way as kondowole flour, the nutritional value of the flour, its most important use is in
Whole roots or Peel Cassava Peeled cut pieces maphumu roots roots Soft mass ( ) Soak
Squeeze or Soak Sun dry pound
Pounded mass Soft roots (1) Peel Dried mass (unpeeled) (2) Sun dry (1) Sun dry (as balls or small pieces) Pound (2) Pound
Sweet or alcoholic Ferment Kondowole Mix with maize, Composite Ferment Sweet or beers floursorghum, rice, flour alcoholic Cook or millet flour beers Bake Cook Bake Sima Sima (a cooked Bakery (cakes, paste) bread, scones)
Figure 1. Processing kondowole flour from cassava roots, and its uses, Malawi.
290 Cassava Flour in Malawi: Processing, Quality, and Uses
Tanzania
Zambia
Likoma and Chizumulu Islands (Mozambique)
Mozambique
Figure 2. Cassava-growing areas in Malawi ( = major growing areas; = scattered crops; = lake). 1 = Karonga District; 2 = Nkhotakota District; 3 = Zomba District; = town of same name as district. (After Nyirenda.)
Cassava Peel and Peeled roots (whole roots or cut pieces) roots wash (1) Sprinkle (1) Cover Sun dry (1) Pound water with banana leaves (2) Sun dry (2) Sun dry (2) Sun dry
(1) Add millet, sorghum, or maize flour Composite Dried mass (makaka) Sima (2) Mill or pound flour Ferment Bake Pound Bakery Sweet or products alcoholic beers Bake Bake Mix with sorghum, Ferment Ntandaza flour Sweet or Ferment maize, or millet flour (ntandasha, Composite flour alcoholic beers mtandasha) Cook Cook
Sima (a cooked paste) Sima
Figure 3. Processing ntandaza flour from cassava roots, and its uses, Malawi.
291 Cassava Flour and Starch: Progress in Research and Development brewing. The resulting beer is 12-month-old plants, whereas those reported to be of superior quality. processed into kondowole and ntandaza flours for cyanogen Information on the quality of determination varied from 20 to cassava flour produced in Malawi was 22 months in age. limited until 1986, when our work began (Saka, n.d.). The processing of Processing the flours cassava into various forms affects the nutritional value of the final products Kondowole. Four roots from (Longe, 1980). The levels of total each of three plants, totalling 12, cyanoglucosides, linamarin and from each of three varieties were lotaustralin are also affected during peeled, washed, and soaked in processing (Lancaster et al., 1982). deionized water (volume not recorded) in plastic wash basins for 7 days. Hydrolysis of cyanoglucosides by The resulting soft mass was washed an endogenous enzyme, linamarase, with clean water, broken down (by liberates the highly toxic substance, hand) into small pieces while hydrocyanic acid (HCN) via removing floury material in the acetocyanohydrin (de Bruijn, 1971). process, and left to dry on trays in the The presence of nonglucosidic sun for 7 days. The dried product cyanogens (NGC; acetocyanohydrin was then ground in a blender and and HCN) limits cassava use (Nartey, sieved. 1978). Cyanide has a lethal dose of 0.5 to 3.5 mg HCN/kg of body weight. The data (Tables 1 and 2) Although the reports of acute cyanide obtained for kondowole flour were intoxication and death among taken from 20 to 22-month-old plants cassava-eating populations are and the soft, soaked roots were made infrequent, ample evidence exists that into balls and sun dried for 67 h. goiter and cretinism (due to iodine Samples of kondowole flour were deficiency) are exacerbated, and that provided by the Cassava Commodity diseases such as tropic ataxic Team, Makoka Agricultural Research neuropathy and epidemic spastic Station. paraparesis (konzo) are caused by long-term ingestion of cyanide from Ntandaza. Twelve roots were cassava (Rosling, 1987). selected as above, peeled, and either pounded or cut longitudinally and We studied the nutritional value transversely to produce chips. The and cyanogen content of the two chips were sun-dried on trays and the Malawian cassava flours to ascertain dried material (makaka) was their quality. processed into flour, using a blender and sieve. The pounded roots were sun dried for 2 to 3 days (Table 1). Material and Methods Chemical analysis Cassava samples Analar grade chemicals and solvents Tuberous roots were obtained from were used. Fresh roots and cassava the Makoka Agricultural Research flours were analyzed for moisture, Station, Zomba, and from the “D. C. ash, crude fiber, fat, crude protein, Munthali” Research Farm, Biology and minerals (Ca, P, Mg, and K), Department, Chancellor College, using standard procedures (Osborne Zomba. The roots analyzed for and Voogt, 1978). The carbohydrate nutritional value were from content was calculated by difference.
292 Cassava Flour in Malawi: Processing, Quality, and Uses
Table 1. Cyanogen content of cassava flours (mg HCN/kg dry wt) produced in Malawi. Values are means of samples, with SE in parentheses.
Flour type Moisture Cyanogens Total cyanogen (%) reduction Total Non- Free (% of initial content) glucosidic
Kondowole (n = 21) 11.8 2.91 0.75 0.69 98.0
Ntandaza (n = 8):
Poundeda, 11.4 116.8 25.5 1.6 79.7 sun dried (1.2) (6.2) (0.7) (0.2) (1.3)
Poundedb, 4.88 54.4 4.80 0.39 80.0 sun dried (0.12) (2.5) (0.20) (0.06) (2.5)
Chipsc, 14.6 51.6 12.4 3.05 88.9 sun dried (0.5) (3.1) (0.6) (0.20) (1.0) a. ‘Nyambi’, a bitter variety, was peeled, pounded, and sun dried at 30 ± 1 °C for 48 h. b. ‘Gomani’, a bitter variety, was peeled, pounded and sun dried at 30 ± 1 °C for 72 h. c. ‘TMS 1230158 (OP)’, a bitter variety, was peeled, cut into chips and sun dried at 30 ± 1 °C for 72 h.
Table 2. Composition of cassava roots and products from our work and some literature sources (on dry wt basis). Each value is the mean of 12 roots with ± SE.
Component Roots Ntandaza flour Kondowole flour (Malawi study) Malawi Longe, Malawi Williamson, Longe, study 1980 study 1975 1980
Moisture (%) 55.9 ± 4.9 13.44 ± 2.66 11.80 10.77 ± 2.72 12.00 12.00 Ash (%) 2.21 ± 0.45 2.15 ± 0.18 2.05 0.91 ± 0.30 1.79 Crude fat (%) 1.23 ± 0.44 0.87 ± 0.33 0.46 0.70 ± 0.30 0.24 Crude fiber (%) 2.29 ± 0.39 2.30 ± 0.70 1.62 ± 0.30 Crude protein (%) 3.17 ± 0.62 3.39 ± 0.73 2.04 1.46 ± 0.30 1.70 1.51 Carbohydrate (%) 91.1 ± 1.2 91.0 ± 1.1 90.30 95.3 ± 0.66 95.50 94.40 P (mg/100 g) 82 ± 35 93 ± 27 40 ± 20 Ca (mg/100 g) 54 ± 27 26 ± 12 17 ± 8 63.00 Mg (mg/100 g) 40 ± 17 58 ± 16 32 ± 13 K (mg/100 g) 768 ± 354 877 ± 358 330 ± 138
Cyanogen extraction and analysis were then centrifuged at 8 x 103 g for 10 minutes. The supernatant was To 30 g of flour (60 g fresh roots) in a collected in sample bottles and blender was added 0.1 M of chilled deep-frozen until analysis. The fresh orthophosphoric acid (H3PO4) cassava was extracted in four (200 cm3), with subsequent extraction replicates and the processed cassava according to Cooke’s (1978) method. in duplicates. For the assay of total The milky liquid was poured into cyanogen content, samples were centrifuge tubes. Their weights were prepared according to the acid adjusted until equal and the tubes hydrolysis method of Bradbury et al.
293 Cassava Flour and Starch: Progress in Research and Development
(1991). For NGC (cyanohydrin plus fresh roots. Whereas the dry matter free HCN) and free cyanide, the and Mg contents were increased, the procedure of O’Brien et al. (1991) was fat and Ca levels were decreased. used. In all cyanogen assays, a sodium isonicotinate-sodium Soaking and subsequent sun dimethylbarbiturate coloring reagent drying of cassava provided kondowole was used (Saka, 1992). flour, whose composition was significantly different (at both P = The moisture contents of fresh 0.05 and 0.01) from that of fresh and processed cassava were roots. During this process, the determined gravimetrically after oven carbohydrate content became drying three replicate, 10-g-sample significantly higher while the rest of aliquots at 110 ± 5 °C for 16 h. the analyzed constituents decreased. These were lost as dissolved material during soaking. These findings are Results and Discussion consistent with those reported by Longe (1980). Table 2 presents the mean chemical data for kondowole and ntandaza Table 1 provides the levels of flours and the literature data for total, nonglucosidic, and free cassava flours similarly processed. cyanogens of kondowole and The results show that, despite certain ntandaza flours and presents the similarities, the chemical percentage reductions in total compositions of the two flours were cyanogen content. The results show significantly different at P = 0.05. that the method used to prepare kondowole flour (involving a At 1% level, neither the fat values submerged fermentation stage) was nor the Ca content were significantly more efficient in reducing total different. The chemical data in Table cyanogen content than that employed 2 reveal that, compared with fresh for ntandaza flour. The production of roots, the two cassava flours are kondowole resulted in 98.0% ± 1.6% equally important sources of loss in the total cyanogen content carbohydrates, but with generally while an 82.9% ± 5.2% reduction was lower values in protein, fat, and fiber. achieved during the processing of Their mean nutritional values ntandaza flour. compare well with published data (Longe, 1980) but higher fat levels Mahungu et al. (1987) also noted were obtained by Saka (n.d.). The a 99% reduction in cyanogen content present data fill several gaps and also with methods that involve soaking confirm the limited available roots in water. Saka (1992) recently information on Malawi cassava flour eliminated 70% to 80% of total (Williamson, 1975). cyanogen content by sun drying 1-cm3 cassava chips for 48 h. The Comparison of the chemical residual, total cyanogen content of composition of fresh roots (Saka, n.d.) kondowole flour was 2.91 ± 1.44 mg and the two cassava flours (Table 2) HCN/kg dry wt and of ntandaza flour, indicates that sun drying alone, and 51.6 ± 3.1 to 116.8 ± 6.2. Thus, the soaking in water followed by sun ntandaza flour contained much drying, affect the nutritional value of higher residual cyanogen content cassava. Simple sun drying produced than did the kondowole. The final ntandaza flour, whose dry matter, fat, cyanogen content depends on Ca, and Mg levels were significantly whether the variety contains low different (at P = 0.05) from those of (“sweet”) or high (“bitter”) cyanogen.
294 Cassava Flour in Malawi: Processing, Quality, and Uses
The less bitter, or sweet, varieties was high. The final products may have lower residual cyanogen remain potentially toxic for human content when sun dried (Saka, n.d.). consumption. Pounding of fresh cassava and its subsequent sun The composition of the three drying seem to offer better prospects forms of cyanogens indicates that in achieving low cyanogen content. free HCN is a major component of the NGC in kondowole flour. In contrast, in ntandaza, cyanohydrin Acknowledgments is the major component. Cyanoglucosides also predominate I wish to thank the Research and in ntandaza flour. Publications Committee, University of Malawi; R. F. N. Sauti, Team Leader, High levels of acetocyanohydrin Cassava Commodity Team; the in sun-dried chips have also been Malawian Ministry of Agriculture; the observed by others (Mlingi et al., International Foundation for Science, 1992). Consumption of this type of Sweden, for funding; and Mrs. L. C. cassava appears to lead to high Saka for typing the manuscript. thiocyanate levels in human urine (Mlingi et al., 1992). Plans are currently under way to develop or References upgrade methods for reducing total residual cyanogen and cyanohydrin Bradbury, J. H.; Egan, S. V.; and Lynch, to levels comparable with those in M. J. 1991. Analysis of cyanide in kondowole flour. cassava using acid hydrolysis of cyanogenic glucosides. J. Sci. Food Agric. 55:277-290.
Conclusions Cock, J. H. 1985. Cassava: new potential for a neglected crop. International Cassava and its flours are major Agricultural Development Service (IADS) development-oriented sources of carbohydrates, but have literature series. Westview Press, low values in protein, fat, and Boulder, CO. 191 p. minerals. The protein content could be improved by fortifying with cereal Cooke, R. D. 1978. An enzymatic assay for and legume grains. The use of the total cyanide content of cassava (Manihot esculenta Crantz). cassava flour in Malawi remains J. Sci. Food Agric. 29:345-352. restricted to cooking sima, baking, and brewing. Diversifying and de Bruijn, G. H. 1971. Etude du caractère promoting cassava flour use is cyanogenetique du manioc. Papers. desirable. Wageningen Agricultural University, Wageningen, the Netherlands. 140 p. Soaking and subsequent sun drying of cassava roots greatly DEPD (Department of Economic Planning reduce the high cyanogen levels to and Development). 1987. Agriculture low, safe values for human and animal husbandry. In: Republic consumption. This method of Malawi Statement of Development Policies 1987-1996. Government increased the carbohydrate content Printer, Zomba, Malawi. 22 p. of the cassava, but other nutrients were reduced considerably. Simple Hahn, S. K. 1989. An overview of African sun drying was less effective in traditional cassava processing and reducing total cyanogens, especially utilization. Outlook Agric. 18(3):110-118. when the initial cyanogen content
295 Cassava Flour and Starch: Progress in Research and Development
Lancaster, P. A.; Ingram, J. S.; Lim, M. Y.; Saka, J. D. K. 1992. Determination of and Coursey, D. G. 1982. cyanogen content of cassava (Manihot Traditional cassava-based foods: esculenta Crantz), using sodium survey of processing techniques. isonicotinate-sodium Econ. Bot. 38:12-45. dimethylbarbiturate. Paper presented at the Fifth International Chemistry Longe, O. G. 1980. Effect of processing on Conference in Africa, 27-31 July, the chemical composition and energy University of Botswana. value of cassava. Nutr. Rep. Int. 21(6):819-828. ______. n.d. Nutritional value and hydrocyanic acid content of Malawi Mahungu, N. M.; Yamaguchi, V.; Almazan, cassava (Manihot esculenta Crantz) A. H.; and Hahn, S. K. 1987. and cassava flour. Malawi J. Sci. Reduction of cyanide during Technol. (In press.) processing of cassava into some traditional African foods. J. Food Sauti, R. F. N. 1982. Country report: Malawi. Agric. 1:11-15. In: Root crops in East Africa: proceedings of a workshop held at Mlingi, N. L. V.; Assey, V. D.; Poulter, N. H.; Kigali, Rwanda, 23-27 Nov. 1980. and Rosling, H. 1992. Cyanohydrins International Development Research from insufficiently processed cassava Centre (IDRC), Ottawa, Canada. induces ‘konzo’, a newly identified p. 104-106, 122-128. paralytic disease in man. In: Westby, A. and Reilly, P. J. A. (eds.). ______; Saka, J. D. K.; and Kumsiya, Proceedings of a Regional Workshop E. G. 1989. The composition and on Traditional African Foods - Quality nutritive value of cassava-maize and Nutrition, 25-29 Nov. 1991, Dar composite flour. In: Alvarez, M. N. es Salaam. International Foundation and Hahn, S. K. (eds.). Proceedings of for Science (IFS), Uppsala, Sweden. the Third Eastern and Southern p. 163-169. Africa Regional Workshop Root and Tuber Crops, 7-11 Dec., 1988, Nartey, F. 1978. Manihot esculenta (cassava): Mzuzu. International Institute of cyanogenesis, ultrastructure and Tropical Agriculture (IITA), Ibadan, seed germination. Munksgaard Nigeria. p. 71-75. International Pubs., Copenhagen, Denmark. 262 p. Van Drongelen, A. 1992. Reasons for choices in cassava processing, the case of O’Brien, G. M.; Taylor, A. J.; and Poulter, Mulanje. Wageningen Agricultural N. H. 1991. Improved enzymic assay University, Wageningen, the for cyanogens in fresh and processed Netherlands. 67 p. cassava. J. Sci. Food Agric. 56:277-289. Williamson, J. 1975. Manihot esculenta Crantz: useful plants of Malawi. Osborne, D. R. and Voogt, P. 1978. The University of Malawi, Zomba, Malawi. analysis of nutrients in foods. p. 155-157. Academic Press, London, UK. 251 p.
Rosling, H. 1987. Cassava toxicity and food security. Tryok Kontakt Pubs., Uppsala, Sweden. 40 p.
296 SESSION 6:
NEW PRODUCTS The Potential for New Cassava Products in Brazil
CHAPTER 34
THE POTENTIAL FOR NEW CASSAVA PRODUCTS IN BRAZIL1
G. Chuzel*, N. Zakhia**, and M. P. Cereda***
Introduction Given the various intermediate products of cassava (e.g., chips, Cassava is an important crop in flours, and starch); the array of Brazil, with an annual production of current applications in human and 22-25 million tons. Production animal nutrition and in industry; systems, processing methods, and the and the numerous traditional degree of technology employed vary cassava preparations, it is possible between the four major cassava to visualize a broad range of regions (Amazônia, Northeast, cassava-based markets. The key Central South, South), according lies with new technologies and the to agroecological location and development of novel products to fit socioeconomic conditions. Farinha, a current and potential markets. toasted flour, comprises the principal market, accounting for 70%-80% of To innovate products within cassava production, but price and the existing matrix of traditional demand fluctuate greatly. and new products and their respective markets, the following Price fluctuations influence the factors should be considered: area of land cultivated, adoption of new technology for production, and (1) The evolution of a successful income of cassava producers, mainly starch sector such as that of small-scale farmers. Diversification France during the last would help stabilize prices of both 20 years; cassava flour and fresh roots. (2) Current trends in Brazil toward Establishing new markets for cassava product diversification; and and its products would enhance the (3) Proposed strategies for the value of cassava cultivation and short and medium terms. establish important links between small-scale agriculture and expanding markets. The Evolution of the Starch Sector in France
* CIRAD/SAR, stationed at the Faculdade de The modern French starch Ciências Agronômicas (FCA), Universidade industry, based on maize or potato Estadual Paulista (UNESP), São Paulo, Brazil. starch, provides a relevant example ** CIRAD/SAR, Montpellier, France. of an industry evolving in search of *** UNESP/FCA. new products and markets in both 1. No abstract was provided by the authors. food and nonfood sectors.
299 Cassava Flour and Starch: Progress in Research and Development
250,000
1234
1234 200,000 1234 1234
1234
1234
150,000 1234 123
1234 123
1234 123 100,000 1234 123 1234 123 Starch (t)
1234 123 123
1234 123 123 123
50,000 1234 123 123 123 1234
1234 123 123 123 123 1234
1234 123 123 1234 123 123 123 1234 0 Paper Others Textiles Foundry Adhesives Food industry and chemicals Pharmaceuticals Corrugated paper
Markets
12
12
Figure 1. Starch markets in France, 1954-1987 ( = 1954; 12 = 1987). Nonfood uses in 1954 comprised 52% of starch production, which totalled 145,000 t; in 1987, 58% of 710,000 t. Note: “Others” include such markets as drilling muds, flocculation agents, building materials, and mining.
Before the 19th century (1) An almost five-fold increase in starch utilization. The annual Only wheat starch was produced in growth rate in the last decade of France, principally for starching starch utilization in the European fabrics, powdering wigs, and gluing Community (now the European papyrus or paper, that is, exclusively Union) remained above 3.8%; nonfood uses. The convergence of (2) A steadily increasing quantity of glucose production, and that of beet starch (from 52% to 58%) is sugar, with the industrial revolution of destined for nonfood uses; the 19th century, transformed this (3) A profound change in user small-scale activity into a large markets: increased use by paper industry, providing a wide range of industries, and pure chemistry raw materials suited to a considerably and pharmaceutical sectors, with broadened range of applications. The a reduced use in the textile discovery of dextrins in the 1830s, industry. then of linters in the 1890s, and, most significantly, modified starches in the To confront these developments, 1940s gave rise to the industry of the starch industry has had to adapt today. completely its product range, creating new products and seeking new 1960s to 1980s applications. The industry has learned how best to add value to, The approach adopted by the adapt, or modify the functional and developing starch sector was “new and physicochemical properties of starches traditional products for new and (e.g., viscosity, capacities for binding, traditional markets.” For example, the thickening, adhesion, flocculation, market for starch products in France and dispersion). A matrix of product from 1954 to 1987 (Figure 1) was versus market, and new versus characterized by: traditional can be observed:
300 The Potential for New Cassava Products in Brazil
Traditional products New products
Traditional markets Native and modified starches: Cationic starch: Food Paper Paper Textiles Borated dextrins: Adhesives
New markets Native starch: Isoglucose: Corrugated paper, ceiling Beverages tiles, wall panels CM starch: Pregelatinized starch: Pharmaceuticals Flocculation agents Lipophilic starches: Crosslinked, stabilized starches: Beverage emulsions, Frozen and microwave foods encapsulation
Organic acids, AA, enzymes
Approach adopted by the French starch industry during the 1960s to 1980s.
From the above matrix, the (c) Reticulated and stabilized following points are worth noting: starches which prevent undesirable effects associated (1) Traditional markets for new with certain modes of cooking products: The development of (e.g., heating by microwave cationic starches with increased causes phase separations, retention capacity has varying degrees of swelling, considerably strengthened breakage of the crust, and existing markets in the paper nonuniformity of flavors and industry. aromas). (2) Traditional products in new markets: The food marketing (3) New markets for new products: sector has largely evolved during The development of isoglucose has the last few years, opening new opened up large markets, especially markets for such modified in the U.S. drinks industry. starches as: Likewise, fermentation techniques using starch as a substrate (a) Pregelatinized starches, have opened up chemical, cold-soluble starches; pharmaceutical, and other markets, reticulated starches (more providing a wealth of derived stable under cooking products. conditions, in the preparation of For the next decade ready-to-use foods); (b) Oxidized starches, resistant The starch industry is now following a to retrogradation, for frozen similar approach to strengthen and products; diversify its markets for the next decade:
301 Cassava Flour and Starch: Progress in Research and Development
Traditional products New products
Traditional markets Native and modified starches: Fat and sweetner substitutes: Food Paper (retention rate) Paper Low calorie foods Textiles
New markets Starch, pregelatinized starch: PHB/V, Polylactic acid: Biodegradable plastics Biopolymers
Carboxylic starches, surfactants: Bioconversions Thermoplastic starches Detergents Cyclodextrins
Approach adopted by the French starch industry for the next decade.
Responding to future demands These new products and applications depend on previously This approach enables the starch well-identified target markets: the sector to respond to emerging demands Brazilian cassava industries still from existing or potential users such as have not moved toward new nutritional considerations, quality products for new markets. This is requirements, or environmental highly risky in terms of research concerns. and development, whether generating new technologies or identifying new markets and The Cassava Industry in Brazil marketing strategies, particularly as these industries lack the Traditionally, cassava is consumed as necessary human and financial fresh roots, or processed into farinha, resources. polvilho azedo, or starch for food, paper, and textile industries. Although The French starch sector, to farinha remains the principal market develop as described above, devotes for cassava, the Brazilian cassava more than 2% of its turnover to industry has taken a series of research and development— initiatives to diversify markets: impossible to imagine in the current Brazilian context. (1) New markets for traditional products: A new market for In an attempt to overcome this polvilho azedo (sour starch), a lack of resources, the Centro Raizes naturally fermented starch with Tropicais (CERAT), together with bread-making properties, is the Universidade Estadual Paulista developing urban fast-food outlets; (UNESP), brought together about and for farinha in mining. 50 researchers from several (2) New products for traditional Brazilian research institutions and markets: In particular, the food development-support institutions, industry is increasing its use of to help the industrial sector follow native or modified cassava the “new products for new markets” starches, such as cationic starch approach, along the lines of the and maltodextrins. Frozen cassava following matrix: chips is another new product.
302 The Potential for New Cassava Products in Brazil
Traditional products New products
Traditional markets Quality and new cassava varieties: High-fiber biscuits Fresh consumption Fat substitutes: Farinha Meat products, ice-creams
Polvilho azedo Cyclodextrins
Starch: Food, paper, textiles
New markets Farinha, native starch: Glucose syrups: Grits substitutes in Food industry beer brewing
Polvilho azedo: Maltose syrups (MFT): Premixes for food industry Brewing, acid-fermented drinks, polysaccharides, packaging, uses of byproducts
Brazilian cassava industry: present and potential future products and markets.
The research initiated under Bibliography project EU-STD3 (value-added products, byproducts, and waste Ansart, M. 1990. Le poids et la diversité des products of small and medium-scale débouchés industriels de l’amidon. cassava primary processing industries Industrie Agro-alimentaire, juin 1990. p. 541-545. in Latin America) falls within the scope of this initiative, particularly in terms Leygue, J. P. 1992. Les utilisations of new products for new markets. non-alimentaires des céréales: quatre débouchés porteurs. Perspect. Agric. Some of these research efforts 167:40-54. will transfer to the industrial world of Light, J. 1990. Modified food starches: why, secondary processing (e.g., use of what, where and how. Cereal Foods farinha or cassava starch in beer World 35(11):1081-1092. brewing as a substitute for maize grits, formulation of sour starch-based Swinnels, J. J. M. 1990. Industrial starch chemistry: properties, modifications premixes for production of, for and applications of starches. AVEBE example, pão de queijo). The business no. 05.00.02.006EF. community has already expressed interest—an indication of the relevance of the approach adopted.
303 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 35
EXTRUSION PROCESSING OF CASSAVA: FORMULATION OF SNACKS
N. Badrie and W. A. Mellowes*
Abstract Introduction
Acceptable snack-type extrudates Cassava (Manihot esculenta Crantz) is were produced, using flour from grown mainly in tropical developing cassava (Manihot esculenta Crantz) as countries where it is a primary source the main ingredient. Various formulas of carbohydrates for millions of people of cassava flour blended with other (Coursey, 1978; Nestel, 1973). The ingredients were tested. Extrusion roots do not store well after harvest processing was carried out, using a and usually begin to deteriorate laboratory extruder (Wenger X-5, within 2 to 4 days (Odigboh, 1983). single-screw) under constant Processing helps solve the storage conditions, where feed moisture was problem (Sammy, 1971) and 11%, barrel temperature 120-125 °C, increases the usefulness of screw speed 520 rpm, and feed rate cassava. 250 g/min. Sensory attributes of color, flavor, and texture, and overall Snack foods now comprise an acceptability were rated by panelists important part of the daily nutrient on a 5-point scoring system. Analysis and calorie intake of many of variance indicated significant consumers. They can be sweet or differences (P < 0.01) for sensory savory, light or substantial, and may attributes and for formulas. Flavor even be endowed with attributes such scored the highest, reflecting the as “healthy” or “just for fun” presence of popular spices in the (Tettweiler, 1991). Among West blends. Formula F4 received the Indians, spicy snacks are especially highest scores for flavor and color and popular. for acceptability. All formulas were acceptable, except for F7 and F8, Extrusion processing is one of the which contained yeast. Color was fastest growing, and most important, most attractive when 0.1% turmeric food-processing operations of recent was added. years (Harper, 1981a; Paton and Spratt, 1984). The food industry has invested considerable research in the extrusion processing of a wide range of foodstuffs, developing many successful products (Linko et al., * Food Technology Unit, Department of Chemical Engineering, Faculty of 1981), including snacks, baby foods, Engineering, University of the West Indies, cereals and starches, and/or St. Augustine, Trinidad, West Indies. vegetable proteins (Harper, 1981b).
304 Extrusion Processing of Cassava: Formulation of Snacks
Cooked, extruded snacks are Cassava roots generally prepared from cereals such as de-germinated maize meal, and Wash rice and wheat flour (Smith, 1976). (remove surface dirt)
Hand-peel In Trinidad and Tobago, maize (immersing roots in water) meal is a major imported ingredient for extruded foods such as ready-to- Slice eat snacks. Limited work has been (1-3 mm thick with a done on the extrusion of cassava, 2 to 5-cm diameter) resulting in the absence of cassava extrudates on the local market. The Dry (at 60 °C for 3.5 to 4 h) objectives of this research were to (1) use cassava flour as the main Grind ingredient for a snack product under suitable processing conditions, and Sieve (particle size ranges (2) determine, by sensory evaluation, from 0.25 to 0.84 mm) the acceptability of extrudates of various formulas. Cassava flour 8.5%-9.0% d.b.
Materials and Methods Pack (in HDPE bags) Store (in plastic Feed ingredients containers with lids)
Cassava roots of the local variety Blend ingredients ‘Maracas Blackstick’ were processed (allow to equilibrate) into flour (Figure 1) within 48 hours of harvesting. The flour was then Adjust feed moisture (to 11% d.b.) blended with small amounts of additional ingredients to yield a Extrusion variety of formulas. These ingredients were powdered spices, such as onion Pack extrudates (0.2%, 0.5% w/w), garlic (0.2%, (in HDPE bags) 0.5%), chili (0.2%, 0.5%), turmeric (0.1%, 0.2%, 0.5%, and 1.0%), and Store (at 4 °C in plastic paprika (0.2%, 0.5%); sucrose (0.5%); containers with lids) uniodized salt (1.0%, 1.5%); Sensory evaluation monosodium glutamate (MSG, 1.0%), dried skimmed milk (0.5%); soybean Figure 1. Procedures for extruding cassava flour oil (4.0%); yeast (1.0%, 1.5%), and blends. (HDPE = high-density defatted soybean flour (5.0%, 10.0%). polyethylene.)
The feed sample of each formula was left to equilibrate for 24 h and plastic containers. Extrudates were adjusted to the targeted feed moisture presented to panelists for sensory of 11% d.b. The samples were again evaluation within 2 days of extrusion. left to equilibrate at 4 °C for 24 h and, before extrusion, were allowed to A single-screw laboratory reach ambient temperature. After extruder, with a 2.5-cm diameter, was cooking, the extrudates were packed used (Wenger X-5, Wenger in high-density polyethylene (HDPE) Manufacturing Company, Sabetha, bags and stored at 4 °C in sealed Kansas). The screw was of decreasing
305 Cassava Flour and Starch: Progress in Research and Development pitch with a compression ratio experienced in the sensory evaluation (channel depth in feed zone to of food products. They rated the channel depth in metering zone) of sensory attributes of color, flavor and 2:1 and length to diameter (L/D) ratio texture, and overall acceptability of 15:1. The die diameter was according to a scale where 5.0 mm and land length 9.0 mm. The 1 = unacceptable; 2 = poor; die plate was attached to a breaker 3 = acceptable; 4 = good; and plate, 6.0 mm thick. The extruder 5 = excellent. In addition, comments consisted of eight stainless steel, were required. jacketed head sections. Each section in the barrel was uniformly supplied Extrudates of uniform size were with steam generated from a served in sealed polyethylene bags, Sussman Electric Boiler (Hot-Shot randomly coded by three digits. Two Model, MB-6, Automatic Steam samples were presented per session Corporation, NY). Barrel temperature and water was provided for rinsing was monitored by thermocouples between samples. Scores assigned to mounted inside the barrel, using a each quality attribute and to the temperature recorder (Type BD41, formulas were subjected to analysis of Kipp and Zonen, Holland). A feed variance to determine any significant hopper with paddle agitator ensured differences. Sensory means were uniform feed flow into the extruder separated by Tukey’s test (Larmond, barrel. 1977). Sensory evaluation was conducted at the University’s Food Extrusion conditions Technology Laboratory, between 10:00 a.m. and 11:00 a.m. Badrie and Mellowes (1991b) had already established suitable extrusion conditions for cassava flour: blends Results and Discussion should be extruded at constant conditions of feed moisture 11% d.b., Proximate composition barrel temperature 120-125 °C, screw speed 520 rpm, and feed rate of The proximate composition of cassava 250 g/min. flour was crude protein, 1.5%-1.6%; crude fat, 0.6%-0.7%; crude fiber, Proximate analysis 1.7%-1.8%; ash, 1.5%-1.7%; total carbohydrate, 85.2%-86.2%; and The proximate composition of cassava starch amylose, 16.4%. Crude flour and the crude protein (%) of protein of defatted soybean flour defatted soybean flour were ranged from 52.1% to 52.2%. When determined by AOAC (1965) 5% or 10% defatted soybean flour was procedures, except for crude fiber added to cassava flour, the crude (AACC, 1983). Total carbohydrate protein content rose from was determined by difference. 1.38% ± 0.02% to 5.20% ± 0.03 or to Amylose was estimated with a rapid 7.49% ± 0.05%, respectively. colorimetric method (Williams et al., 1970). Low protein (< 3%) staples such as cassava do not provide adequate Sensory evaluation protein for human requirements, even when ingestion exceeds caloric Extrudates were evaluated by 10 requirements. In contrast, diets with panelists, who were students and cereals (8%-10% protein) can meet faculty staff of the University of the adult protein requirements (Cheftel et West Indies. They were widely al., 1985). Soya protein, rich in
306 Extrusion Processing of Cassava: Formulation of Snacks amino acid lysine (Harper, 1981b), in bursts. Only at 11% feed moisture can be used to fortify cassava flour. was a more uniform moisture distribution and, thus, a more elastic Soybean flour was added to the dough achieved, resulting in a smooth cassava flour blend to increase the surface texture. Foods with a lower protein content, improve quality, and moisture content also tend to be more increase the yellow color of the viscous, the greater pressure extrudate. Badrie and Mellowes differential resulting in better puffing. (1992b) found that soybean flour makes extrudates more attractive and The optimal expansion of cassava yellower, resulting in a change of flour extrudate can be related to its Munsell color notation from 4.62Y microstructure. Scanning electron 6.38/1.75 to 5.04Y 6.46/2.19 at 5% microscopy on cassava flour soybean flour or to 5.30Y 6.46/3.10 extrudates (Badrie and Mellowes, at 10%. Thermal processing of food 1991a) at 11% feed moisture revealed can increase the potential for wide porous air cells with thin cell interaction between lipids, proteins, walls. Extrudate expansion was carbohydrates, and their breakdown positively correlated (P < 0.05, products (Bruechert et al., 1988). r = 0.80) to the water solubility index Maillard browning appeared the most (WSI). At 11% moisture, the lowest likely reason for the color change. texture values were recorded. Low-moisture extrusion, according to Badrie and Mellowes (1992b) also Harper (1989), can cause more found, however, that adding soybean mechanical damage (shear stress) to flour reduced extrudate expansion the feed, resulting in a softer texture. and increased bulk density. At 11% moisture, a more intense and Extrudate expansion was negatively attractive color (4.62Y 6.38/1.75) was correlated with crude protein also obtained. (P < 0.01, r = -0.88). Extrusion was stable between 100 Establishing processing conditions and 125 °C, producing uniform, puffed products. Temperature Sensory attributes of extrudates increases from 100-105 °C to depend on extrusion conditions and 120-125 °C brought corresponding feed material. Badrie and Mellowes increases in extrudate expansion. At (1991b) established suitable higher temperatures (130-155 °C), processing conditions, evaluated on extrudates became increasingly the bases of extruder performance irregular, degenerating to rapidly and the physical and chemical ejected fragments. Temperatures properties of extrudates. above 125 °C probably resulted in a weakened structure and led to a Optimal expansion (2.82) rougher extrudate surface texture. occurred at a feed moisture of 11% d.b.—the minimum moisture Establishing formulas necessary to obtain a flow of the extrudate through the die (at Because spicy snacks are a particular 120-125 °C, screw speed 520 rpm, favorite of West Indians, powdered and feed rate 250 g/min). Lower feed flavorings of onion, garlic, chili, moisture either blocked the rotation paprika, and turmeric were included of the screw (there was no transition in the blends. Turmeric, a major from the original floury nature to the ingredient of curry powder, ‘melted’ state typical of extrusion) or also lent a more appealing yellow the extrudates emerged from the die color. Other flavor enhancers were
307 Cassava Flour and Starch: Progress in Research and Development sucrose, salt, and monosodium For the second formula, F2, glutamate. Dried skimmed milk adjustments were made to F1: the provided both protein and flavor. level of turmeric was reduced from Soybean oil was added at 4% level—a 1% to 0.5%, and salt was reduced level at which Badrie and Mellowes from 1.5% to 1.0%. Panelists again (1992b) showed that lowest bulk found the extrudates hard, too spicy, density and highest extrudate too yellow, and tasting of turmeric, expansion resulted, linked to although all sensory scores were increases in the WSI and total acceptable (Table 1). reducing sugars. Hsieh et al. (1990), working with maize meal extrudate For formula F3, turmeric and produced by a twin-screw extruder, paprika were reduced from 0.5% to reported that adding salt and sugar 0.2%. A significantly better flavor enhanced radial and axial expansion and more acceptable color resulted but reduced bulk density and (Table 1), but extrudates of F4 (0.1% breaking strength. turmeric and 1.5% spices) gained the highest overall acceptability, scoring For the first formula (F1), sensory highest in both color and flavor. scores for all parameters were better than acceptable, that is, higher than For F5, spice content was further 3 (Table 1). But panelists’ comments reduced to 0.9%, but panelists found revealed that the color was unevenly the extrudates too bland, and the distributed and too yellow. flavor rating dropped from 4.25 (for Extrudates were also too spicy and F4) to 3.83. too salty, with a distinct taste of turmeric. Expansion was acceptable, To improve texture of the but texture was slightly hard and the extrudates, the percentage of defatted extrudate overly dense. soyflour was increased from 5% to
Table 1. Sensory attribute scoring of cassava flour blend extrudates.†
Formula Color Flavor Texture Overall Overall mean acceptability‡ for formula
F1 3.18 bcdef 3.20 ef 3.42 abcd 3.24 bcdef 3.26 bcdef
F2 3.23 bcde 3.27 e 3.43 abc 3.30 bcde 3.37 bcde
F3 3.50 abc 3.92 ab 3.45 abc 3.59 ab 3.62 ab
F4 3.69 a 4.25 a 3.40 abcd 3.82 a 3.79 a
F5 3.58 ab 3.83 bcd 3.42 abcd 3.57 abc 3.60 abc
F6 3.48 abcd 3.81 bc 3.50 abc 3.55 abcd 3.59 abcd
F7 2.85 efg 2.91 efg 2.10 e 2.60 g 2.62 g
F8 2.95 efg 3.07 efg 2.67 e 2.88 efg 2.89 efg
Overall mean 3.31 a 3.53 ab 3.17 abc 3.32 bc of attribute§
† Columns: scores followed by the same letter are not significantly different among formulas at P < 0.05. Rows: values of overall mean attribute followed by the same letter are not significantly different among attributes P < 0.05. LSD of formulas = 0.43; LSD of attribute = 0.25. ‡ On a scale where 1 = unacceptable, 3 = acceptable, and 5 = excellent. § Mean of 10 replications.
308 Extrusion Processing of Cassava: Formulation of Snacks
10% (F6), thereby reducing the total Table 2. Analysis of variance of sensory scores carbohydrate level. The result was a for cassava flour blend extrudates. reduced extrudate expansion and an Source of df MS F increased bulk density, but no variation significant change in texture. Adding cassava starch to cassava flour (i.e., Attributes 3 0.18 5.63** increasing the total carbohydrate) Formulas 7 0.65 20.31** tended to increase all textural Error 21 0.032 attributes, the extrudate becoming less elastic or springy (Badrie and Total 31 Mellowes, 1992b). ** Significant at P < 0.01.
Badrie and Mellowes (1992b) showed that when soybean flour was acceptable), with texture (3.17) added to cassava flour, the registering the lowest, although also percentage of noncarbohydrate better than acceptable. Only F7 and components (in particular, crude F8 proved unacceptable (Table 1). protein) increased. Extrudate Panelists commented on the unique expansion was negatively correlated flavor of cassava extrudates. with crude protein (r = -0.88, However, they tended to rate texture P < 0.01). Bulk density was lower because of their tendency to negatively correlated (r = -0.96, compare cassava extrudates with the P < 0.05) to extrudate expansion and popular maize extrudates. Cereals positively correlated to crude protein have excellent expansive properties (r = 0.89). and are well suited to thermal extrusion. To reduce the bulk density of the extrudates, instant dry yeast was As Stanley (1986) observed, incorporated in the blend at 1.0% (F7) texture is the major obstacle in and 1.5% (F8). However, these remodelling ingredients into additions resulted in unacceptable acceptable foods. To produce sensory scores. The effectiveness of products in the highly acceptable or sodium bicarbonate (baking powder) excellent categories, panelists or maize amylose on reducing recommended lightening texture and extrudate bulk density will be reducing bulk density and surface assessed in a later study. Although irregularity of extrudates. amylose tends to provide surface regularity and lightness, cassava The F4 overall rating of 3.79 was starch or flour has too low an amylose significantly (P < 0.05) higher than content (16.4%) and produces denser, other formulas. less radially expanded extrudates (Badrie and Mellowes, 1992a). Conclusions Sensory scores Distinctive and acceptable extrudates Analysis of variance indicated can be produced, using cassava flour significant differences at both 5% and as the main ingredient. The study 1% level for sensory attributes and pointed to texture, bulk density, and formulas (Table 2). surface regularity as areas requiring attention. Flavor achieved the Flavor received the highest overall highest overall rating, attributable to mean score (3.53, i.e., better than the 1.5% spice in most formulas.
309 Cassava Flour and Starch: Progress in Research and Development
Except for F7 and F8, to which dry ______and ______. 1992b. Soybean yeast had been added, all formulas flour/oil and wheat bran effects on Manihot were acceptable. Formula F4 characteristics of cassava ( esculenta Crantz) flour extrudate. emerged as the best overall product, J. Food Sci. 57(1):108-111. having scored the highest for flavor and color. Color was found to be Bruechert, L. J.; Zhang, Y.; Huang, T. C.; most attractive when 0.1% turmeric Hartman, T. G.; Rosen, R. T.; and was added. Ho, C. T. 1988. Contribution of lipids to volatiles generation in extruded corn-based model systems. J. Food Other formulas, especially those Sci. 53(5):1444-1447. incorporating local ingredients, can be tried. Successful development of Cheftel, J.; Cuq, J. L.; and Lorent, D. 1985. extruded cassava products for the Amino acids, peptides and proteins. In: Fennema, O. R. (ed.). Introduction snack food industry in the West to food chemistry. Marcel Dekker, Indies could give rise to competition New York, USA. p. 245-369. with popular, established maize-based products, the meal for Coursey, D. G. 1978. Cassava: a major food which must be imported. Extrusion crop of the tropics. Paper presented at a workshop on cyanide is a rapidly growing food-processing metabolism by the European operation and extruded spicy snacks Organization at Canterbury, UK, are popular in the West Indies, but 14-18 August 1978. more trials and consumer-type sensory evaluations are necessary Harper, J. M. 1981a. Extrusion of foods, vol. 1. CRC Press, Boca Raton, FL, before cassava-based extruded snacks USA. can enter the local market. ______. 1981b. Extrusion of foods, vol. 2. CRC Press, Boca Raton, FL, USA.
References ______. 1989. Food extruders and their applications. In: Mercier, C.; Linko, AACC (American Association of Cereal P.; and Harper, J. M. (eds.). Extrusion Chemists). 1983. Approved methods, cooking. American Association of vol. 1. 8th ed. St. Paul, MN, USA. Cereal Chemists, St. Paul, MN, USA. p. 1-16. AOAC (Association of Official Agricultural Chemists). 1965. Official methods Hsieh, F.; Peng, I. C.; and Huff, H. E. 1990. of analysis. 10th ed. Washington, DC, Effects of salt, sugar and screw speed USA. on processing and product variable of corn meal. J. Food Sci. 55(1):224-231. Badrie, N. and Mellowes, W. A. 1991a. Texture and microstructure of Larmond, E. 1977. Laboratory methods for cassava (Manihot esculenta Crantz) sensory evaluation of foods. flour extrudate. J. Food Sci. Department of Agriculture, Ottawa, 56(5):1319-1322, 1364. ON, Canada.
______and ______. 1991b. Effect of Linko, P.; Colonna, P.; and Mercier, C. 1981. extrusion variables on cassava High temperature - short time extrudates. J. Food Sci. extrusion cooking. In: Pomeranz, Y. 56(5):1334-1337. (ed.). Advances in cereal science and technology, vol. 4. American ______and ______. 1992a. Cassava Association of Cereal Chemists, St. starch or amylose effects on Paul, MN, USA. p. 145-235. characteristics of cassava (Manihot esculenta Crantz) flour extrudate. J. Food Sci. 57(1):103-107.
310 Extrusion Processing of Cassava: Formulation of Snacks
Nestel, B. 1973. Current utilization and Smith, O. B. 1976. Extrusion cooking. In: future potential for cassava. In: Altschul, A. M. (ed.). New protein Nestel, B. and MacIntyre, R. (eds.). foods, vol. 2(B). Academic Press, New Chronic cassava toxicity, vol. 1. York, USA. p. 86-120. Proceedings of an inter-disciplinary workshop held in London. Stanley, P. W. 1986. Chemical and structural International Development Research determinants of texture of Centre (IDRC), Ottawa, ON, Canada. fabricated foods. Food Tech. p. 11-26. 40(3):65-68, 76.
Odigboh, E. U. 1983. Cassava production, Tettweiler, P. 1991. Snack foods worldwide. processing and utilization. In: Chan, Food Tech. 45(2):58-62. Jr., H. T. (ed.). Handbook of tropical foods. Marcel Dekker, New York, USA. Williams, P. C. Z.; Kuzina, F. D.; and Hlynka, p. 145-200. I. 1970. A rapid colorimetric procedure for estimating the amylose Paton, D. and Spratt, W. A. 1984. content of starches and flours. Cereal Component interactions in the Chem. 47(4):411-420. extrusion cooking process: influence of process conditions on the functional viscosity of the wheat flour system. J. Food Sci. 49(5):1380-1385.
Sammy, G. M. 1971. Some problems in the establishment of fruit and vegetable processing in Trinidad and Tobago. In: Sammy, G. M. (ed.). Postgraduate seminar on food technology, session 2. Food Technology Series No. 5. Faculty of Engineering, University of the West Indies. p. 1-16.
311 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 36
THAI CASSAVA FLOUR AND STARCH INDUSTRIES FOR FOOD USES: RESEARCH AND DEVELOPMENT1
Saipin Maneepun*
Introduction Recently, lysine has become available and is used as a nutrient in feed Cassava has become a major cash mills. At present, the Thai crop for Thailand: in 1993, production Government is planning to support was about 21 million tons, and research that would help diversify the increasing (TDRI, 1992). About 90% use of cassava starch in various of total production is exported, mainly industries to prevent falling prices. to Europe. Although cassava is mostly Cassava starch industries only processed into pellets and chips for produce 50%-70% of their total animal feed, the volume of these capacity, and thus have potential for products has decreased slightly during further development. the last decade in favor of cassava flour and starch for domestic industry and export (Table 1). Production and Development of Cassava In 1990/1991, although 96 Flour cassava starch processing factories were registered, only 55 were Two kinds of cassava flour-processing operating. Total production capacity factories operate in eastern Thailand: was 1.5-1.8 million tons, of which traditional and modern. 50% was for export, 25% for food-processing, and 25% for nonfood Traditional factories industries. Flour-processing factories were first In 1991, the 55 cassava starch built in the early history of cassava factories could be classified into 46 production in Thailand. The model of starch factories and 9 modified-starch operation—a family business that factories. Monosodium glutamate employs now-obsolete technology—is (MSG) processing ranks highest still common in some parts of among those cassava starch Thailand. Cassava roots are first processing industries manufacturing crushed, then soaked in water. The amino acids (Table 2; Rodsri, 1993). resulting starch is extracted, sun dried, and pulverized into flour, which, however, is inferior in quality * Institute of Food Research and Product and bulk. It is used for making such Development (IFRPD), Kasetsart University, products as noodles, desserts, and Bangkok, Thailand. sago, most of which are sold on local 1. No abstract was provided by the author. markets.
312 Thai Cassava Flour and Starch Industries for Food Uses:...
Table 1. Export of cassava sago, chips, pellets, and starch from Thailand, 1982-1991, in metric tons.
Year Sago Chips Pellets Starch Total prod. (x 1000)
1982 2,397 523,059 6,892,786 396,754 17,788 1983 2,948 279,913 4,554,332 359,298 18,989 1984 5,831 137,808 5,975,136 449,183 19,985 1985 7,566 123,702 6,474,503 482,309 19,263 1986 5,243 35,699 5,842,468 435,154 15,255 1987 7,420 72,833 5,777,137 353,594 19,554 1988 6,663 312,460 7,334,446 452,199 22,307 1989 9,223 130,201 9,185,466 501,329 24,264 1990 8,447 210,814 7,316,368 531,365 20,701 1991 10,060 113,205 6,269,458 549,022 19,705
SOURCE: Rodsri, 1993.
Table 2. Use of cassava starch in Thailand. (1) Cassava roots are weighed and measured for their starch content. Uses Percentage of total use (2) The roots are precleaned by a soil separator, then passed through a Direct consumption 26 cleaning machine and peeler. Industry: Peeling makes extracting starch Monosodium glutamate 19 easier. Glucose syrup 15 (3) The roots are then crushed and Paper 9 liquid starch is extracted, leaving a Food 7 Sago 6 cake, which is sun dried before Textiles 2 being used as a supplementary Timber 1 feed or for producing cassava chips and pellets. Other 15 (4) The liquid starch is purified by Total 100 passing it through a sulfur vapor
SOURCE: Rodsri, 1993. to rid the starch of sap. (5) Water is then filtered out and the starch dried mechanically. It is then packed and shipped to Modern factories markets.
Many flour-processing factories have On the average, 1 kg of fresh roots been modernized since World War II to yields 200 g of starch and between produce high-quality cassava flour for 40 and 90 g of cake. Cassava flour export and use in domestic industry. quality depends on the manufacturing The role of cassava thus changed process. If the process is efficient and from being a local crop for domestic clean, the flour will be of high quality. consumption to a major commercial Quality is judged by granule size; flour crop for export. At present, modern color, smell, and purity; fiber and ash processing equipment is being contents of flour; humidity, acidity, developed for export to neighboring and viscosity of liquid starch; and countries such as China, Vietnam, cake. At present, a cassava breeding and Indonesia. The capacity of program has been established to such equipment ranges from 50 to develop varieties that have high starch 100 t/day (Figure 1). In modern content: 22%-24%, depending on the processing: growing season.
313 Cassava Flour and Starch: Progress in Research and Development
Inclined chain conveyor Root chopper Inclined Root sieve belt Washer Fresh cassava roots conveyor Rasper
Horizontal Separator belt conveyor Extractor Extractor Pressed pulp Screw press
Cooling cyclone
Drying cyclone Sifter and bagging Tapioca starch Flash product dryer Drying cyclone
Centrifuge
Screw feeder
Figure 1. Processing tapioca starch, Thailand. (From Thai Tapioca Starch Industries Trade Association, 1976, personal communication.
Standard Specifications for Standards for cassava flour and Starch for Export and starch used locally were established Local Markets in 1974 by the Thai Industrial Standard, Ministry of Industry: The Ministry of Commerce has “Flour/starch obtained from cassava established specifications for roots (Manihot utilissima) has starch inspecting and controlling cassava granules of microscopic appearance, flour and starch for export. consisting of a cluster of two to eight granules, each granule measuring Certified products must be 5 to 35 µm and having an average inspected according to Ministry diameter of 15 µm. Most starch standards and/or importer granules are oval or truncated at one specifications. “Cassava end to form a kettledrum shape while flour/starch” is defined as that the other end has a cutting edge with “obtained from cassava root [as] a the inner surface concave or white or cream-colored powder that irregularly flat. Starch granules does not include modified starch.” clearly show an eccentric hilum with Cassava flour and starch are graded segment lines.” The quality of local at three levels, each with its own flour and starch is classified into specifications (Table 3; Ministry of three grades (Table 4; Ministry of Commerce, 1993). Industry, 1978).
314 Thai Cassava Flour and Starch Industries for Food Uses:...
Table 3. Export standards for cassava flour and starch at three grades, Thailand, 1993.
Characteristics Supreme grade First grade Second grade
Starch (day basis) (%) 85 83 80 Moisture content (%) 13 14 14 Ash (%) 0.2 0.3 0.5 Fiber (cm3/50 g flour) <0.2 <0.5 <1.0 pH 4.5-7.0 3.5-7.0 3.0-7.0 Particle size (mesh hole = 150 µm) (%) 99 97 95
SOURCE: Ministry of Commerce, 1993.
Table 4. Local standards for cassava flour and starch at three grades, Thailand, 1978.
Characteristics Grade 1 Grade 2 Grade 3
Starch (dry basis) (%) 97.5 96.0 94.0 Moisture content (%) 13 14 14 Ash (%) 0.15 0.30 0.50 Ash (acid insoluble) (%) 0.05 0.10 0.15 Protein (%) 0.3 0.3 0.3 Fiber (cm3/50 g flour) 0.2 0.5 1.0 pH 4.5-7.0 3.5-7.0 3.0-7.0 Particle size (mesh hole = 150 µm) (%) 1 3 5
SOURCE: Ministry of Industry, 1978.
Both bulk and retail packers can Cassava Flour and Starch in stamp the appropriate grade mark on Local Food Products packets for consumers’ selection. Retail packs are for home cooking. Studies on incorporating cassava Information on using composite flour flour into bakery goods for the local (that includes cassava flour) in market require research on the eating foodstuffs is readily available at local habits of the population. Because bookshops. consumers prefer wheat-based products, industries using cassava Various food products from rice, flour have developed products made bean, and wheat flours can improve from mixtures of cassava and wheat their texture by substituting with flours. Such composite flours impart cassava flour or starch. a unique taste and texture to the products. Because cassava flour and starch are mostly processed with water, they Sponge cake made with cassava contain no hydrocyanic acid. The flour Thai Standard for Cassava/Flour Starch Committee does not accept the The effect of composite flour on the codex standard for edible cassava quality of sponge cake has been flour acceptable to African countries. studied by Saencharoenrat The African Regional Standard (1990). He tested four kinds of wheat permits cassava flour to contain flour (chlorinated cake flour = CCF, 10 mg/kg of hydrocyanic acid unchlorinated cake flour, all-purpose (FAO and WHO, 1992). flour, and bread flour) with different
315 Cassava Flour and Starch: Progress in Research and Development levels of cassava flour: 0%, 20%, 40%, was 40%. Results showed that the 60%, 80%, and 100%. He found that, spread was high, compared with that when the level of cassava flour of wheat flour. Most tasters found the substitution was increased, protein composite-flour cookies to be content, ash content, and damaged palatable. starch content decreased. Changes in moisture content and pH, however, Spread in composite-flour cookies depended on the kind of wheat flour. can be markedly reduced by using The gelatinization temperature of an emulsifying agent. Patco-3 composite flours was in the same (50% sodium stearic lactylate and 50% range as that of the type of wheat flour calcium stearic lactylate) and BV-15 used, whereas peak viscosity in gel (commercial cookie improver), used at formation increased. Water 0.5% (flour basis), produced a cookie absorption, dough stability, resistance with a spread factor not significantly to extension, and extensibility also different from that of cookies made decreased as the mixing tolerance with commercial cookie flour. Nor were index increased. Sponge cakes made its organoleptic properties significantly with these composite flours were then different from those of the commercial evaluated. cookie.
Results showed that the different The storage life of composite-flour kinds of wheat flour and the levels cookies was not significantly different of substitution affected several from that of wheat-flour cookies. characteristics of cakes. Increased Composite-flour cookies could keep an levels of substitution increased batter acceptable texture for about 3 months viscosity and specific volume of cake, when stored in polythene bags, but decreased specific gravity of batter rigid plastic containers (polyvinyl and palatability of cakes. The kind of chloride [PVC]), or tin boxes. The wheat flour used affected ease of 40%-composite flour can reduce cookie cutting the cake (bread flour scored prices by almost 2%, compared with the highest), pH (lowest with CCF), wheat flour. The production of and palatability (highest with CCF). composite-flour cookies has been Palatability scores agreed with total scaled up, using cassava flour as a raw cake scores. The ideal composite flour material. was 40% cassava flour and 60% CCF, that is, no significant differences were Where cookies were made with found (at P = 0.05) in palatability 15% full-fat soybean flour, cassava between cakes made from composite flour could substitute wheat flour by as flour and cakes from 100% wheat much as 50% (Boonyasirikool et al., flour. 1987). The product still has more than 10% protein. Palatability tests showed Cakes stored at room temperature no significant difference between these could be kept for only 2 days, whereas two types of cookies. Using vanilla and refrigerated cakes lasted at least cocoa flavors can enhance product 7 days. Ease of cutting increased with quality and make it highly acceptable. storage time, and moisture content and palatability decreased. Chemically Modified Cassava Cookies made with cassava flour Starch for Use in the Food Industry Chananithithum (1986) found that the maximum substitution of cassava Cassava starch is a typical root starch flour for wheat flour in baking cookies and is used in the production of
316 Thai Cassava Flour and Starch Industries for Food Uses:... foodstuffs and adhesives. Direct use of Various modified cassava starches have native cassava starch is more frequent been developed and promoted for use in in home cooking than in industry. the food industry. Root starch granules, when cooked, swell more and are more fragile (i.e., Cassava starch phosphate they break down easily and thin out during stirring) than are cereal starch Industries manufacturing transparent granules. The viscosity of these starch noodles, sauces, and custards have pastes can be determined by using a been encouraged to use cassava starch Brabender viscoamylograph. After phosphate as a replacement for mung stirring, tapioca starch shows the bean starch (Maneepun and Sirirojana, lowest viscosity (Figures 2 and 3). 1990) and as a thickening agent in When certain chemicals are sauces (Sirirojana, 1987) and custard introduced, they cross-link within the spreads (Parvet, 1988). granule, tighten up the molecular network, restrict granule swelling, and Niyomvit et al. (1990) studied the so stabilize the viscosity of starch use of premixed cassava starch pastes against breakdown by agitation. phosphate and native cassava starch
Time (minutes) 30 60 90 120 150 800 700 2 600 500 1 400 3 300
Viscosity (BU) 200 100 4 0 65 95 95 50 50
Temperature (°C)
Figure 2. Amylograph of cassava starch, and cassava starch crosslinked with sodium tripolyphosphate and sodium sulfate at different times. 1 = cassava starch; 2 = cassava starch crosslinked with phosphate for 2 h; 3 = for 4 h; 4 = for 6 h. (From Sirirojana, 1987.)
Time (minutes) 0 10 20 30 40 50 60 70 80 90 100 110 1,000
800
600
400
Viscosity (BU) 200 0 35 50 65 80 95 95 95 95 80 65 50 35 Temperature (°C)
Figure 3. Amylograms of starches. = acetylated cassava starch (6%); .. = wheat (9%); = maize = (8%); = potato (4%). (From Saencharoenrat, 1990.)
317 Cassava Flour and Starch: Progress in Research and Development for the traditional Thai dessert, “kanom hydrolyzing a hot-water-soluble, chen.” Their experiments showed that acetylated di-starch phosphate the cassava starches changed their with excess sodium hydroxide (IFRPD, viscosity after cross-linking with the 1993, unpublished data). The phosphate (Figure 2). Products were digestion of sodium hydroxide is almost prepared for tasting panels, who equivalent to acetyl content. determined that the premixed cassava starch phosphates, of 15% (2 h), 30% Amylograms showed that the peak (4 h), or 15% (6 h), were highly viscosity and stability of viscosity were acceptable. The characteristics higher in A/C starch than in potato, required were transparency, easily maize, or wheat starch (Figure 4). separating layers, and stable texture. Swelling power is also greater in A/C The Instron Food Tester showed that starch than in wheat or maize starch the texture was 60%-70% more stable but lower than in potato starch than that of unmodified, mixed (Figure 5). The A/C starch is stable cassava starch. under conditions of freeze-thaw, high cold storage, and acidity. It has a short Acetylated cassava starch texture and high transparency. The (A starch) product used depends on the viscosity of final products and is recommended Most countries permit the use of A for use in sauces made with vinegar or starch as a direct food ingredient. The fruit juice. Because A/C starch has a degree of substitution (DS) of starch good affinity with raw meat and is hard acetate is determined by hydrolyzing to retrograde, it can be used for boiled with excess sodium hydroxide. The fish paste, deep-fried fish paste, fish digestion of sodium hydroxide is ham, sausage ham, sausages, and almost equivalent to acetyl content meat balls. (Institute of Food Research and Product Development [IFRPD], Both A and A/C starches can be unpublished data). Amylograms used for making wheat noodles showed that the peak viscosity and (oriental type), resulting in smooth stability of acetylated cassava starch noodles whose texture when cooked is are comparable with those of starches stable during cold storage. from potato, maize, and wheat (Figure 3). The acetyl substitution Cassava starch ether (hydroxypropyl) lowered the rate of retrogradation of cooked pastes. The cassava starch ether is used as a food ingredient in most countries. When cassava substituted The degree of substitution of 30%-50% of starches from mung bean, hydroxypropyl in starch ether is potato, or sweetpotato in the ascertained by hydrolyzing with hot manufacture of jelly bean sticks, the sulfuric acid to propionaldehyde, resulting product was smooth, and had which is then measured with a good texture, gloss, and flexibility. spectrophotometer after complexing with ninhydrin (IFRPD, 1993, Acetylated and slightly unpublished data). Amylograms cross-linked cassava starch showed that cassava starch ether has (A/C starch) a high peak viscosity and good stability, which means it can reduce This is called acetylated di-starch retrogradation of cooked paste phosphate and is usually (Figure 6). This starch ether is being cross-linked with phosphate. The DS tried out in sauce-making (acid of acetate can be determined by conditions).
318 Thai Cassava Flour and Starch Industries for Food Uses:...
Time (minutes) 0 10 20 30 40 50 60 70 80 90 100 110 1,000
800
600
400
Viscosity (BU) 200 0 35 50 65 80 95 95 95 95 80 65 50 35 Temperature (°C)
Figure 4. Amylograms of starches. = acetylated and slightly crosslinked cassava starch (6%); = wheat (9%); = maize (8%); .. = potato (4%). (From IFRPD Laboratory, 1993-1994, personal communication.)
30
20
10 Swelling power (times) 0 50 60 70 80 90 Heating temperature (°C)
Figure 5. Swelling power of starches. = acetylated and slightly crosslinked cassava starch; = potato; .. = wheat; = maize. (From Saencharoenrat, 1990.)
One gram of starch and 49 g of water were mixed in a centrifuge tube. The tube was then heated at several temperatures, each fixed for 30 min, while the mixture was stirred. After heating, the mixture was centrifuged at 3,000 rpm for 20 min. The precipitate was then weighed. Swelling power was measured as the quantity of water 1 g of starch could absorb at a given temperature.
Time (minutes) 0 102030405060708090 1,000
800
600
400
Viscosity (BU) 200 0 45 63 90 90 50 50 Temperature (°C)
Figure 6. Amylogram of cassava starch ether (hydroxypropyl). (From IFRPD Laboratory, 1993-1994, personal communication.)
319 Cassava Flour and Starch: Progress in Research and Development
Standards for modified starch for Products of Chemical and the food industry Microbial Processing of Cassava Starch as Ingredients Standards were introduced to Used by Food Industries encourage cassava starch factories to produce modified cassava starch Some industrial processes use cassava for the local market (Ministry of starch as raw material to manufacture Industry, 1992). First published in final products that are themselves January, 1992, these standards are used as ingredients in foodstuffs. upgrading modified-starch products Such products are typically either as manufacturers apply for grade seasonings or sweeteners. and have certification. The standards deal been developed locally and overseas. with different types of modified Most of the technology has been starch, physical and chemical brought from developed countries with additives used for modification, experts as consultants. Local residues and limiting properties institutions sometimes collaborate to indicators, and methods of analysis. promote further local development.
Fifteen types of modified The processes are complex, starches exist: pregelatinized starch, involving chemical and microbial dextrin, thin boiling starch, alkaline technologies that require sophisticated treated starch, bleached starch, machinery. The final products are oxidized starch, di-starch costly. Table 5 shows estimates of the phosphate, starch succinate, cassava starch consumed by these hydroxypropyl starch, starch industries (TDRI, 1992). acetate, monostarch phosphate, hydroxypropyl di-starch phosphate, The seasoning industry acetylated di-starch adipate, acetylated di-starch phosphate, and Thailand has three seasoning combination chemical process factories, one of which uses cassava starch. starch and the other two molasses as
Table 5. Estimates of cassava starch use in seasoning and sweetening industries, Thailand, 1992.
Products Cassava starch used Yield from 1 kg (t/year) cassava starch (kg)
Seasoning industry:
Monosodium glutamate and lysine (1991) 97,977 0.42
Sweetening industry:
High fructose 15,000 1.00 Liquid glucose 30,000 0.90-0.95 Dextrose (monohydrous) 12,000 1.75 Dextrose (anhydrous) 100 0.50 Sorbitol 28,000 1.20
SOURCE: TDRI, 1992.
320 Thai Cassava Flour and Starch Industries for Food Uses:... raw material for processing MSG. reactors for starch digestion. This MSG and lysine products are process, however, requires new expected to be in high demand in equipment (such as a digestion tank, the future, especially from filter technique, and evaporator), food-processing industries, for both which needs to be designed and local and export markets. Lysine developed. processing, a new industry, has raised the consumption of cassava Sweetening products also need starch in the last few years. In to be developed and their use manufacturing MSG, cassava starch promoted in various food industries is hydrolyzed by using α-amylase that manufacture, for example, soft enzyme and α-amyloglucosidase to drinks, beverages, ice creams, canned change starch into glucose. The foods, and bakery products. Because fermentation is then continued with of severe competition with the bacteria Micrococcus glutamicus or sugarcane industry, food-processing Brevibacterium spp., which are given industries are slow to develop urea as nutrient supplement. sweeteners from starches, including Eventually, crystalline MSG is cassava starch. formed. The process was first developed in Japan, imported to Thailand, and promoted within the Conclusions local food industry. Because cassava production is The sweetening industry predicted to increase during the next decade, research and development are Thailand first processed glucose needed on cassava use, for both local syrup in 1950, glucose powder in and overseas markets. The Cassava 1976, and sorbitol in 1980. In 1989, Development Institute Foundation the total sweetening industry has been established to study the consisted of seven factories: four nature of the crop’s production, use, producing glucose syrup, one and marketing. At present, cassava is producing sorbitol, and the still faced with falling prices, which remaining two, various sweetening affect growers, industries, and products (Sathetkeingkai, 1989). traders. Animal feed and nonfood products can also be developed as the At present, the country’s market requires, thus adding value to production of glucose syrup is about the crop. 76,000 t, which is sufficient for local needs. Considering the potential uses of glucose syrup, it could be References used in the confectionery industry, which would add value to cassava Boonyasirikool, B.; Ratarpar, V.; and starch by as much as 55%. The Phuphat, P. 1987. Quality consumption of confectionery improvement of Kaset-cookie. In: Proceedings of 25th Annual Meeting, products is still low, and needs to be Agroindustry Session, Kasetsart developed and promoted both locally University, 3-5 February, Thailand. and regionally. Faculty of Agroindustry, Kasetsart University, Thailand. p. 27-35. Glucose syrup can be processed Chananithithum, P. 1986. Partial in various ways. At present, a substitution of wheat flour in cookies continuous process is being with tapioca flour. M.S. thesis. developed to replace the batch Chulalongkorn University, Thailand. process by using several types of p. 84-92.
321 Cassava Flour and Starch: Progress in Research and Development
Res. Prod. Dev.) 20(2):105-114. FAO and WHO (Food and Agriculture Parvet, S. 1988. Product development of Organization of the United Nations and coconut custard spread. M.S. World Health Organization), Codex thesis. Chulalongkorn University, Alimentarius Commission. 1992. Codex Thailand. p. 70-90. standard for edible cassava flour— African regional standard—CODEX Rodsri, K. 1993. Trend of cassava STAN 176-1991. Eighth session of the development in agroindustry. Codex Committee on Cereals, Pulses J. Agroind. 4(3):16-22. and Legumes, CX/CPL 92/9, June, 1992. FAO/WHO Food Standards Saencharoenrat, C. 1990. Effects of tapioca Program, Rome, Italy. 17 p. flour substitution in wheat flour on the quality of sponge cake. M.S. Maneepun, S. and Sirirojana, V. 1990. Novel thesis. Chulalongkorn University, uses of modified cassava starch in the Thailand. p. 90-118. Asian food industry. In: Cassava breeding, agronomy and utilization Sathetkeingkai, A. 1989. Trend of research in Asia: proceedings of the investment of glucose syrup. Third Regional Workshop, Malang, Northeastern Economic Center, Indonesia, October 22-27. CIAT, Cali, Industrial Economic Division, Colombia. p. 388-407. Permanent Secretary Office, Ministry of Industry, Bangkok, Ministry of Commerce. 1993. Draft standard Thailand. for cassava flour/starch. Bangkok, Thailand. 12 p. Sirirojana, V. 1987. Quality improvement of tapioca starch by chemical Ministry of Industry. 1978. Standard for modification. M.S. thesis. cassava flour/starch. Bangkok, Chulalongkorn University, Thailand. Thailand. 20 p. p. 70-87.
______. 1992. Standard for modified TDRI (Thailand Development Research starch for food industry. Bangkok, Institute). 1992. Cassava: in the Thailand. 22 p. next decade. Bangkok, Thailand. . p. 2-1 to 2-37. Niyomvit, N.; Kanchanapakornchai, A.; and Rodporn, S. 1990. Production of “Kanom Cham” premix from tapioca and modified tapioca. Food (Inst. Food
322 Yuca Rava and Yuca Porridge:...
CHAPTER 37
YUCA RAVA AND YUCA PORRIDGE: THE FUNCTIONAL PROPERTIES AND QUALITY OF TWO NOVEL CASSAVA FOOD PRODUCTS1
G. Padmaja, C. Balagopalan, S. N. Moorthy, and V. P. Potty*
Introduction relative economy of their preparation (Balagopalan et al., 1988). Before Cassava (Manihot esculenta Crantz) is being promoted in potential markets, an important food staple for about these two products were evaluated for 500 million people of the tropical their quality, rheological and pasting world (Cock, 1985). Cassava roots behavior, and residual cyanogen are processed by several traditional contents. The results are reported in methods, which vary widely from this paper. region to region. Usually, these techniques are intended to reduce the level of cyanogenic glucosides in the Materials and Methods roots and improve palatability and shelf life of the resultant products Yuca rava and porridge were (Cooke and Maduagwu, 1978). While prepared (Figure 1) from three fermented food products from cassava cassava varieties: the low-cyanogen are popular in many African cultivar H 1687; and two countries, preparations from high-cyanogen cultivars, H 165 and dehydrated flour and those from H 226 (Table 1). Normally, varieties cooked fresh roots are preferred in requiring less cooking are preferred Asian and many Latin American for preparing rava and porridge as the countries. starch in the roots does not gelatinize completely within the 10-min cooking Yuca rava and porridge are two time. This technique of partial novel food products made from gelatinization, or parboiling, helps in cassava roots at the Central Tuber the partial swelling of starch Crops Research Institute (CTCRI), granules. The dried, parboiled chips Trivandrum, India. These products are powdered to obtain the finer are likely to capture the Indian food fraction called “porridge” and the market because of the ease and coarse fraction called rava.
Conventionally, rava is prepared from round cassava chips which are put into boiling water. An attempt was made to find out whether * Division of Postharvest Technology, Central cyanogen retention in parboiled chips Tuber Crops Research Institute (CTCRI), could be reduced with a smaller chip Trivandrum, India. size. The round chips (1 cm thick) 1. No abstract was provided by the authors. were either quartered to equal
323 Cassava Flour and Starch: Progress in Research and Development
Cassava roots
Washing and peeling
Parboiling by steeping in boiling water for 10 min at 100 °C
Decanting
Parboiled chips
Sun drying for 36 h or oven drying for 24 h at 70 °C
Disintegrator
Sieving
Large fraction Medium-sized Small fraction fraction (porridge) (rava)
Figure 1. Manufacturing rava and porridge from cassava, India.
Table 1. Initial content of cyanogens (mg/kg A parallel study was undertaken DM) in cassava cultivars. to find out whether an initial Cultivar Cyanogensa presoaking of cassava chips for varying periods helps remove CG NGC FC cyanogens from the roots. Round and H 1687 88.97 37.27 31.21 quartered chips, as well as strips, were soaked for 30 min, 1 h, 2 h, or H 165 271.15 45.67 31.25 3 h in standing water (1:4 w/v), then H 226 214.12 26.81 20.98 the water was drained off. Rava and a. CG = cyanogenic glucoside; NGC = nonglucosidic porridge were prepared from these cyanogen (acetone cyanohydrin + free); FC = free chips as normal. cyanide. The total and intermediate (nonglucosidic, i.e., acetone portions or cut into strips of uniform cyanohydrin, plus free) cyanogens, width before being used to make rava and free cyanide were quantified in and porridge. the rava and porridge prepared from
324 Yuca Rava and Yuca Porridge:... the three cultivars. The methods for preparations from cassava. Yuca rava extraction and initial stages of and yuca porridge are two novel cyanogen determination up to the products that can be easily prepared, formation of cyanogen chloride were have an acceptable shelf life, and are adopted from O‘Brien et al. (1991). tasty. The coupling of cyanogen chloride was done with the barbituric acid Cyanogen changes pyridine reagents used in the Nambisan and Sundaresan (1984) The residual cyanogenic glucosides procedure. (CG) in rava made from the low-cyanogen cassava cultivar The viscographic behavior of rava H 1687 ranged from 17.5-21 mg/kg and porridge samples from the three DM and, in porridge, from cultivars was studied with a 14.5-24.5 mg/kg DM, according to Brabender viscoamylograph. A the type of chips (Table 2). These concentration of 10%-20% by weight ranges were much lower than those of sample was studied at a heating for the products made from the two rate of 1.5 °C per minute. The peak high-cyanogen cultivars, H 165 and viscosity at 97 °C and viscosity after H 226. The initial CG values were cooling were recorded. The swelling much lower for H 1687 roots volumes were determined by standard (88.97 mg/kg DM), compared with the procedure (Schoch, 1964). A sample high-cyanogen cultivars (Table 1). of 400 mg rava or porridge was suspended in 40 ml water, heated to For each variety, however, the CG 95 °C, maintained at that content among the three types of temperature for 15 min, then cooled chips (round, quartered, and strips) and centrifuged at 2,200 rpm for did not vary significantly when they 15 min. The volume of the gelatinous were put directly into boiling water, precipitate obtained was taken as the parboiled for 10 min, dried, and swelling volume. powdered to make rava and porridge (Table 2). The lack of variation may Starch and sugar contents of rava be a result of the rapid loss of and porridge were determined by a linamarase activity at 100 °C as the standard titrimetric procedure (S. N. roots were directly exposed to this Moorthy, personal communication). temperature. Using 80% alcohol, sugars were extracted from samples by standing The extent of cyanogen removal overnight. The remaining residue was during the boiling of cassava roots hydrolyzed with 2N HCl to convert depends on boiling time, volume of starch to sugars. These released water used, and size of root piece sugars were quantified through (Padmaja, 1993). Ezeala and Okoro ferricyanide titration (S. N. Moorthy, (1986) reported that, after 35 min of personal communication) and the boiling, cyanogens were undetectable starch value computed, using a factor in the roots they used. The initial of 0.9. cyanogen level of 218 mg/kg had dropped to 97 mg/kg within the first 5 min of boiling. However, the Results and Discussion authors had gradually raised the chips to boiling point, taking Of the cassava-consuming areas of 20-25 min. During that time the world, India is perhaps unique in linamarase could act on the making pregelatinized, dried glucosides.
325 Cassava Flour and Starch: Progress in Research and Development
Table 2. Cyanogen content (mg/kg DM)a of rava and porridge made from different types of cassava chips (round, quartered, and strips).
Cultivar Rava Porridge Type of chips CG NGC FC CG NGC FC
H 1687: Round 21.0 35.0 25.0 24.5 32.5 20.0 Quartered 19.0 36.0 22.5 21.5 39.5 17.5 Strips 17.5 26.5 17.5 14.5 25.5 19.0
H 165: Round 86.0 56.0 51.0 74.5 83.5 42.5 Quartered 95.5 46.0 32.0 90.5 56.5 37.5 Strips 108.0 40.5 21.5 100.5 48.5 27.0
H 226: Round 87.0 44.5 37.0 92.0 53.0 46.0 Quartered 70.0 67.0 47.0 82.5 41.5 30.0 Strips 111.0 31.0 27.5 115.0 24.5 21.0 a. CG = cyanogenic glucoside; NGC = nonglucosidic cyanogen (acetone cyanohydrin + free); FC = free cyanide.
Cooke and Maduagwu (1978) also eliminated if chips were put into observed that bound cyanogen was boiling water, even after 10 min of removed at a slower rate only during cooking at 100 °C. boiling and 55% of it was retained after 25 min of boiling. Nambisan Soaking the different types of and Sundaresan (1985) reported that cassava chips for varying periods during 30 min of boiling, only from 30 min to 3 h in standing water 45%-48% of total cyanogen was did not reduce the quantity of eliminated from the roots (varieties cyanogen compared with unsoaked H 165, H 2304, and H 1678). roots (Table 3). Nor did chip type influence cyanogen elimination We found that the CG content during soaking. Similar trends were dropped from about 89 to obtained for low- and high-cyanogen 17-21 mg/kg DM in the low-cyanogen cultivars. But cultivar variations are cultivar H 1678 during 10 min of likely to affect the cyanogen boiling. For the high-cyanogen elimination during soaking. Fukuba cultivars, reductions were from 271 to et al. (1984) obtained 54% 86-108 mg/kg in H 165, and from elimination of total cyanogen from 214 to 87-111 mg/kg in H 226. 1-cm diced roots of variety Bogor 397 during 10 min of soaking, while Fukuba et al. (1984) observed only 5%-6% cyanogen was that cultivar variations strongly eliminated from other varieties. influenced cyanogen elimination in 1-cm diced roots during boiling or The reduction in CG during the soaking treatments. They compared preparation of rava and porridge the effect of slow with rapid boiling. indicates that cyanogen hydrolysis They found that, while 70% of total takes place during parboiling. The cyanogen was eliminated from cubes free cyanide contents of the rava brought to boiling point, only and porridge obtained from each 30%-35% of total cyanogen was variety by various techniques vary
326 Yuca Rava and Yuca Porridge:...
Table 3. Effect of soaking chips on cyanogen content (mg/kg DM)a of rava and porridge made from three cassava varieties, India.
Variety Hours Rava Porridge Type of chips CG NGC FC CG NGC FC
H 1687 (low-cyanogen)
Round: 0.5 24.5 32.5 23.0 25.3 34.8 24.3 3.0 28.5 29.0 22.5 34.3 28.3 19.0 Quartered: 0.5 25.5 29.3 19.8 25.0 29.8 19.0 3.0 32.5 25.0 19.3 32.0 30.8 19.8 Strips: 0.5 27.0 21.8 18.8 27.5 27.5 18.0 3.0 24.0 25.0 18.8 23.0 25.3 17.5
H 165 (high-cyanogen)
Round: 0.5 120.0 66.5 49.5 138.5 68.5 53.0 3.0 116.5 93.0 67.5 108.5 90.5 77.0 Quartered: 0.5 147.5 63.0 51.0 110.5 56.6 49.5 3.0 121.5 58.5 57.0 128.0 48.5 46.0 Strips: 0.5 160.5 67.5 56.0 133.0 60.5 43.0 3.0 105.5 58.5 51.0 144.0 55.0 50.0
H 226 (high-cyanogen)
Round: 0.5 78.0 37.0 17.0 128.0 30.0 19.5 3.0 73.5 21.5 14.5 86.5 30.5 14.5 Quartered: 0.5 78.0 36.5 25.5 122.0 38.5 26.0 3.0 70.0 29.0 19.0 98.5 51.5 40.0 Strips: 0.5 91.5 24.5 17.0 116.0 37.0 26.0 3.0 100.5 21.5 13.5 99.0 39.0 31.0 a. CG = cyanogenic glucoside; NGC = nonglucosidic cyanogen (acetone cyanohydrin + free); FC = free cyanide.
little (Tables 1 to 3). This indicates costs during manufacture of food that the free cyanide formed is rapidly products. lost from boiling water, but that a certain amount of free cyanide is Rheological and swelling retained in dried, parboiled chips. properties
Rapid parboiling, by adding chips Table 4 shows the rheology of rava to boiling water, is insufficient to and porridge samples of the three eliminate cyanogen from varieties. Significant differences in high-cyanogen cultivars. Rigorous swelling volumes exist among the processing is needed to minimize porridge samples of the three cyanogen retention in high-cyanogen varieties. Swelling volumes were cultivars. But for low-cyanogen highest for porridge made from cultivars, such as H 1687, rapid H 226 and lowest for that from parboiling helps reduce operational H 1687. For rava samples, H 165
327 Cassava Flour and Starch: Progress in Research and Development
Table 4. Swelling volume and viscosity of rava and porridge made from cassava roots.
Cassava variety Swelling volume Viscosity properties Type of chips (ml/g) (BU)a
Rava Porridge Maximum viscosity Viscosity breakdown
Rava Porridge Rava Porridge
H 1687: Round 5.00 3.15 360 650 60 280 Quartered 5.00 3.05 350 700 70 350 Strips 5.35 3.75 320 600 30 190 H 165: Round 7.00 7.00 140 680 40 320 Quartered 6.20 6.25 160 820 20 400 Strips 6.25 5.75 150 800 30 360 H 226: Round 3.25 7.00 160 960 20 280 Quartered 3.25 7.50 220 900 30 350 Strips 3.75 7.25 180 870 35 190 a. BU = Brabender units.
had the highest values and H 226, Viscosity data showed rava the lowest. samples to have a different viscosity pattern to that of porridge samples. No relationship was found Porridge showed peak viscosity before between the shape of the chips used 60 °C, whereas rava behaved like a to prepare rava and porridge and starch, with a peak viscosity around swelling volume. The values obtained 75-85 °C. were much lower than those normally observed for corresponding starch Recently, Raja and Ramakrishna samples which have 3-4 times the (1990) found that parboiling affects swelling volumes of rava. The lower viscosity properties. Earlier, Raja et swelling volumes can be attributed to al. (1982) reported that the viscosity the preliminary swelling of starch of powdered, parboiled chips was during parboiling of the chips. Most lower compared with powdered, dried of the starch granules were already chips. This corroborates our findings. swollen during the rava preparation. Starch and sugar changes The swelling volumes observed also indicate an almost equal starch No significant differences were distribution in both rava and porridge observed in the starch content of rava samples. No significant differences in and porridge samples according to swelling volumes exist according to cultivar. Starch content ranged from soaking period of chips, which was 52%-66% in the rava samples and expected. Raja and Mathew (1986) 56%-70% in those of porridge. observed the sedimentation volume of Neither was a relationship found powdered, parboiled chips to increase between chip type and starch content slightly with longer boiling time. But of rava and porridge. Total sugar we observed swelling volume to content was higher for the rava and decrease with parboiling. porridge made from H 226 than from
328 Yuca Rava and Yuca Porridge:...
Table 5. Starch and sugar changes (g/100 g DM) in rava and porridge made from cassava roots.
Cassava variety Rava Porridge Type of chips Starch Sugar Starch Sugar
H 1687: Round 66.18 14.60 64.38 15.74 Quartered 60.18 13.79 63.38 11.36 Strips 55.21 19.84 53.57 16.95 H 165: Round 64.29 13.61 70.31 11.90 Quartered 60.00 12.20 59.60 14.71 Strips 64.29 11.76 62.50 9.09 H 226: Round 67.67 14.81 56.60 20.20 Quartered 52.33 21.05 56.25 17.54 Strips 55.56 20.83 59.21 20.41
H 1687, and lowest for those from Cock, J. H. 1985. Cassava: new potential for H 165. These parameters did not a neglected crop. Westview Press, seem to influence the rheological or Boulder, CO, USA. 191 p. swelling properties of these food Cooke, R. D. and Maduagwu, E. N. 1978. The products (Table 5). effect of simple processing on the cyanide content of cassava chips. J. Food Technol. 13:299-306.
Conclusions Ezeala, D. O. and Okoro, N. 1986. Processing techniques and hydrocyanic acid The rheological and swelling content of cassava-based human properties of the rava and porridge foods in Nigeria. J. Food Biochem. fractions made from the three 10:125-132. cassava cultivars suggest their Fukuba, H.; Igaraschi, O.; Biones, C. M.; and suitability as a wheat substitute for Mendoza, E. T. 1984. Cyanogenic breakfast recipes and certain south glucosides in cassava and cassava Indian sweet dishes. However, the products: determination and retention of cyanogens were found detoxification. In: Uritani, I. and Reyes, E. D. (eds.). Tropical root to be slightly high in the case of the crops: postharvest physiology and high-cyanogen cultivars. We expect processing. Japan Scientific Societies to study detoxifying processes in an Press, Tokyo. p. 225-234. attempt to develop suitable processing technologies for Nambisan, B. and Sundaresan, S. 1984. Spectrophotometric determination of high-cyanogen cultivars, thereby cyanoglucosides in cassava. J. Assoc. increasing demand for food Off. Anal. Chem. 67:641-643. products made from such cultivars. ______and ______. 1985. Effect of processing on the cyanoglucoside content of cassava. J. Sci. Food Agric. References 36:1197-1203.
Balagopalan, C.; Padmaja G.; Nanda, O’Brien, G. M.; Taylor, A. J.; and Poulter, S. K.; and Moorthy, S. N. 1988. N. H. 1991. Improved enzymatic Cassava in food, feed and industry. assay for cyanogens in fresh and CRC Press, Boca Raton, FL, USA. processed cassava. J. Sci. Food Agric. 205 p. 56:277-289.
329 Cassava Flour and Starch: Progress in Research and Development
Padmaja, G. 1993. Cyanide detoxification in ______and Ramakrishna, S. V. 1990. cassava for food and feed uses. Crit. Compositional and pasting Rev. Food Sci. Nutr. 35(4)299-339. characteristics of plain-dried and parboiled cassava (Manihot esculenta Raja, K. C. M.; Abraham, E. T.; Crantz). Food Chem. 38:79-88. Sreemulanathan, H.; and Mathew, A. G. 1982. Studies on improving Schoch, T. J. 1964. Swelling power and textural quality of cassava (tapioca) solubility of granular starches. In: flour: proceedings of a symposium on Whistler, R. L. (ed.). Methods in postharvest technology for cassava. carbohydrate chemistry, vol. IV. Association of Food Science Academic Press, NY, USA. Technology (AFST), Trivandrum, p. 106-108. India. p. 108-116.
______and Mathew, A. G. 1986. Effect of parboiling on hydration and sedimentation characteristics of cassava (Manihot esculenta Crantz) chips. J. Food Sci. Technol. 23:39-41.
330 SESSION 7:
INTEGRATED PROJECTS Integrated Cassava Research and Development Projects...
CHAPTER 38
INTEGRATED CASSAVA RESEARCH AND DEVELOPMENT PROJECTS IN COLOMBIA, ECUADOR, AND BRAZIL: AN OVERVIEW OF CIAT’S EXPERIENCES
B. Ospina*, S. Poats**, and G. Henry***
Abstract cassava markets have diversified and overall demand for cassava has This paper discusses CIAT’s 12-year increased. This has reduced price experience in developing an integrated variability while increasing yields and, cassava research and development as a result, created incentives for project (ICRDP) approach. The origin, adopting improved technologies. Poor justification, methodology, results, farmers’ incomes and employment and lessons learned from this opportunities have also improved approach are presented, using a through the promotion of small-scale, comparative analysis of CIAT’s cassava-based, rural agroindustries experiences in Colombia, Ecuador, with low opportunity costs, especially and Brazil. The ICRDPs have been for landless producers. effective vehicles for CIAT’s Cassava Program to interact with various national research, rural extension, Introduction and development institutions. Existing production, processing, and In 1973, when CIAT’s Cassava marketing technologies have been Program first took shape, few strong validated and adapted to specific agricultural research programs in regional conditions with the ICRDP Latin America focused on cassava. framework. New technologies have Research was well behind, relative to been generated through the synergy of other crops, and emphasized mainly research and development that aspects of production (Pérez-Crespo, ICRDPs promote. Results have 1991). The Cassava Program demonstrated to research and researched germplasm development development institutions, donors, and agronomic practices from governments, and policy makers that 1973 to 1982. Results during this cassava is a crop that can play an period were encouraging, and clearly important role in achieving demonstrated the technical development goals. Through the possibilities of significantly increasing integrated approach, traditional cassava production.
But farmers had no special interest in adopting new cassava * Cassava Program, CIAT, stationed at the production technology to raise Centro Nacional de Pesquisa de Mandioca e efficiency or productivity. With an Fruticultura (CNPMF), Brazil. ** Independent consultant. increasing concentration of Latin *** Cassava Program, CIAT, Cali, Colombia. America’s population in urban
333 Cassava Flour and Starch: Progress in Research and Development centers, preferences shifted from technology to conserve fresh cassava cassava as a basic dietary staple to roots for human consumption and on foodstuffs easier to transport, store, drying technology for the animal feed and exchange. Thus, increasing industry. Research activities on cassava’s use in Latin America was sun-dried cassava chips at CIAT were dependent on developing new started in an attempt to solve quality products that would use cassava in problems in dried cassava chips and its fresh state or transform it to a pellets produced in Thailand and storable or higher value product, and Indonesia and exported to the in developing new markets for these European Union for incorporation into products (Lynam, 1978). animal feed concentrates. Through this work, CIAT gained considerable In 1979, CIAT took an innovative experience in the natural drying step by adding the Utilization Section techniques used in Asian countries. to the Cassava Program, thus extending its responsibilities for crop But this accumulated knowledge research beyond the development could not be applied to Latin and transfer of germplasm and American conditions immediately. A agronomic practices. This move was series of reviews had cast doubts on similar to that of many earlier the Program’s ability to reach farmers projects in numerous countries, with the technologies generated, and especially in Southeast Asia, that so attain increased productivity. After aimed to exploit cassava’s industrial a series of internal planning exercises potential by transforming it focusing on specific social objectives, agroindustrially into meal, flour, a new research and development starch, alcohol, or other derived framework was formulated for the products. In Latin America, relatively Cassava Program. This included the few of these projects met with the need to be directly involved in anticipated success: some, trying to cassava-based, rural development improve production, ran into programs, as a sine qua non marketing problems; others, condition for the crop’s development investing in processing plants, (Cock and Lynam, 1990). encountered problems with the raw material’s price or availability. At the time the Cassava Program was searching for Latin American Analysis of these projects partners and sites to test this highlighted the need for an integrated approach, the Colombian Ministry of approach to cassava production, Agriculture, through the Integrated processing, and market development. Rural Development (DRI) program, Cassava development could not be was pursuing CIAT’s collaboration to expected unless all three areas were solve problems related to increasing simultaneously addressed in an production and decreasing demand integrated fashion. Research and and prices for cassava in the North development activities needed to Coast, an extensive cassava-growing begin by identifying potential area of Colombia. The two entities markets for cassava and its products. developed a collaborative program. Once identified, then product The experiences gained in this and development, processing, production, similar projects in Asian countries and commercialization should begin, over the last 12 years has allowed to develop the market effectively. CIAT to develop the integrated cassava research and development The Utilization Section first project (ICRDP) methodology concentrated on developing discussed in this paper.
334 Integrated Cassava Research and Development Projects...
The Importance of Cassava consists of highly digestible starch. in Latin America Cassava starch has agglutinant properties that make it suitable for Latin America produces 21% of the pelleting in animal feeds, such as world’s cassava. According to the for shrimp or fish, replacing Food and Agriculture Organization expensive artificial agglutinants (FAO, cited in CIAT, 1993), Brazil, (Cock and Lynam, 1990). Paraguay, and Colombia are responsible for 92% of cassava The disadvantages of using production in this region. The fresh cassava roots directly in crop is generally produced in products such as animal marginal, rainfed areas and is concentrates are their bulk, rapid grown by small-scale farmers with perishability, low protein content, limited access to land, inputs, and and the presence of cyanogens in improved technology. In areas all root tissues. These where cassava is grown disadvantages can be overcome by extensively, farmers often have no simple processing techniques, such alternative crops because of as chipping and natural drying. climate and soil limitations. For example, sun drying eliminates most cyanogens from root tissues. Marketing channels available Increasing cassava’s price to cassava growers are usually competitiveness with other limited to one or two traditional carbohydrate sources, and markets per region for either fresh differentiating the uses of its high roots or processed products such quality carbohydrate structure and as farinha da mandioca (toasted composition, help overcome its low cassava flour) in Brazil. As protein content. societies urbanize, demand for processed products may remain Linking small-scale cassava stable or even increase, creating farmers to potential growth shortages and high prices. But the markets via new processing overall demand for cassava tends technology and new product to decline, creating price development is an important option fluctuations and increasing that can help meet several social commercial risks. Lacking policy objectives such as income additional market opportunities for generation among marginal fresh cassava, farmers have no farmers and landless poor (Lynam, incentives to adopt improved 1987). But penetrating alternative production technologies. markets needs competitive farm-level prices, investment in Fortunately, cassava has processing capacity and several characteristics that allow it management, and a coordinated to compete as a multiple source of expansion in production, carbohydrates, especially processing, and use. compared with other root crops, on the basis of price, yield, nutritional The integrated project value, quality, and availability. methodology, developed during the Root dry matter content in cassava last 12 years, aims at coordinating is higher than in other root crops changes in farming systems with (35%-40%), giving optimal changes in the marketing system, conversion rates of 2.5:1 or better. within the framework of Over 85% of root dry matter multi-institutional integration.
335 Cassava Flour and Starch: Progress in Research and Development
Integrated Cassava Research ensures that the correct target region and Development Projects and the most promising markets are (ICRDPs) selected.
Definition Microplanning. Information is gathered to define market An ICRDP is defined as an characteristics, production practices intervention at institutional, and constraints, availability of technological, social, and institutional support, existing farmer organizational levels to link organizations, cassava processing small-scale cassava farmers to new or technologies, and regional government improved growth markets. Thus, development priorities. Then, the demand for production technology is target area is selected for the pilot stimulated with potential to improve project. small-scale farmer welfare. Pilot phase. During this stage, Methodology available technologies can be entirely reworked and adapted to local The ICRDP methodology has four conditions. The project’s institutional stages. These must be phased and organizational framework is sequentially to succeed (Figure 1). determined and serves as the intersection point for cassava Macroplanning. The overall production, processing, and product economic situation of the country or development research. Farmer region initially targeted for an ICRDP organizations are included at this stage is analyzed. The potential demand for and become the project’s permanent cassava and derived products, the actors and decision makers. At the crop’s ability to compete with other end of this stage, enough reliable products and markets, and the information is available to test the potential for cassava production in assumptions made during planning. different regions are considered. The commercial phase is then either Information gathered in this phase justified or rejected.
Macroplanning
Microplanning
Production Product research Pilot phase development research Applied field Pilot evaluation testing of for market and production product technology development
Commercial expansion
Figure 1. Planning integrated cassava research and development projects (ICRDPs).
336 Integrated Cassava Research and Development Projects...
Commercial expansion phase. (2) The development of cassava The use of cassava processing processing and product markets technology and new or improved as income-generating activities; products can now be replicated or (3) The creation of demand for expanded, according to findings of the improved cassava production pilot phase. The new technology’s technology. commercial costs and the resources needed to promote its adoption on a Experiences and results wider scale can now be calculated. This includes credit lines for crop CIAT joined efforts with national production, establishing processing counterpart agencies to initiate capacity and operational capital, and ICRDPs in nine Latin American institutional requirements to train and countries (Table 1). These projects give technical assistance to farmers. have included different products, At the start of the commercial phase, markets, and processing technologies a monitoring system should be and have reached different stages of established, based on the information development. gathering mechanisms begun in the pilot stage. Finally, it must be In Mexico and Peru, the projects remembered that the project failed. The Mexican failure was framework is not a permanent caused by farmers not being mechanism per se and the end committed and involved from the start result of this stage should be a and because the production, self-supporting, economically processing, and commercialization sustainable, cassava-based activities were insufficiently agroindustry. coordinated. The Peruvian project was economically nonviable because Anticipated outcomes the target area was far from markets and another, more profitable, The anticipated outcomes of the enterprise (cocaine processing) was ICRDPs were: competing.
(1) That national research, extension, In the Colombian, Ecuadorean, and development agencies would and Brazilian projects, the CIAT become involved in a concerted Cassava Program, through special effort to improve small-scale funding, managed to have staff farmer welfare through activities members directly involved in project focused on cassava; implementation.
Table 1. Integrated cassava research and development projects in Latin America.
Country Dried chips Flour Starch Fresh roots Leaves for animal for human for feed Human Industrial Human Industrial consumption animal consumption use consumption use feed
Argentina Pilot Bolivia Pilot Brazil Commercial Pilot Pilot Colombia Commercial Pilot Pilot Pilot Commercial Ecuador Commercial Commercial Commercial Commercial Commercial Mexico Failed Panama Commercial Paraguay Pilot Pilot Pilot Peru Failed
337 Cassava Flour and Starch: Progress in Research and Development
The Colombian ICRDP that a large and expanding market for animal feed existed in Colombia, The North Coast is a major cassava and was analyzing the possible use of production zone in Colombia. In dried cassava for this market. The 1990, it accounted for 52% of the two entities teamed up to assess the nation’s cassava production, possibilities of entering this representing 13% of total land under alternative market. cultivation and 20% of the region’s total value of agricultural production Of the various possibilities (Henry et al., 1994). According to analyzed, the most promising seemed Janssen (1986), 40% of the total to be that of establishing cassava small-scale farmer income from producer organizations to operate agricultural production in this area cassava drying plants and sell the is derived from cassava cultivation. dried cassava to animal feed On-farm consumption and fresh factories. This approach appeared cassava sold to urban markets have attractive for two reasons: first, the traditionally been the two main resource-poor farmers in the area commercial outlets for the region’s could not individually afford to cassava crop, although some typical, establish cassava processing processed, cassava-based products infrastructures, whereas as an for human consumption also take a organization they could do so; and, small share of the cassava market. second, the cassava drying process Industrial uses of cassava have been was proposed as a way to create an virtually nonexistent in the region. effective floor price for cassava roots, so that if prices in the fresh market In the late 1970s, the DRI was were high, farmers could sell into already promoting cassava as an these markets and make enough agricultural policy option in the profit to pay off loans on the cassava North Coast. It provided credit and drying plants. Roots unsuitable for technical assistance to increase the fresh market could be sold to the cassava production. drying plants, allowing them to operate at a low level. Conversely, if This traditional, the prices for cassava roots dropped, production-oriented approach was farmers could sell the roots to the relatively successful. Cassava drying plants and still make a profit. production increased rapidly, mainly because of the effect that increased To test this model’s validity credit availability had on through a pilot project, the first intensifying production by farmer cassava natural drying plant to be beneficiaries of the DRI program. operated by farmers was established The rapid growth in production in Betulia, Department of Sucre, in caused saturation in local markets, 1981. The farmers were aided by and prices dropped to such levels CIAT who already had expertise in that farmers were unable to find the cassava chipping and drying buyers to recover their costs. To technology brought from Asia. resolve this problem, the DRI program set up a postharvest Despite their total lack of committee, who contacted CIAT for experience and tradition in cassava help in finding alternative markets processing activities, the Colombian for the region’s cassava production. farmers quickly assimilated and adapted the technology. The initial At the same time, CIAT’s promising results were used to Cassava Program had already found formulate the project’s expansion,
338 Integrated Cassava Research and Development Projects... which underwent two additional Throughout the project’s span, phases: the semicommercial cassava producers and processors (1981-1983), and the replication or received important institutional commercial (1984 to date). support, especially credit lines, technical assistance, and training. By 1991, about 150 cassava Important results were also obtained drying plants were operating in the in the area of improved cassava North Coast (Figure 2), of which production technology. The impact of 105 were owned and operated by the Colombian ICRDP can be best small-scale, cassava producers’ assessed by considering the added associations and/or cooperatives. monetary value of dried cassava’s The remainder were exploited by annual production, foreign exchange private entrepreneurs who, during savings from decreased cereal imports 1987-1991, were rapidly participating for animal feed, added employment in the industry. The fast, widespread opportunities generated in rural areas adoption of diverse types of by expanding cassava production and cassava-drying in the region is now processing activities, and enhanced making accurate monitoring difficult links with goods sectors and services. (Henry, 1992). The Economics Section of CIAT’s During 1991, these 150 drying Cassava Program estimated that, from plants produced about 25,000 t of 1984-1991, the cassava sector in dried cassava chips, corresponding to northern Colombia benefited by 62,500 t of cassava roots—a demand almost US$22 million (Gottret and representing 6.6% of total cassava Henry, 1994). These benefits resulted produced in the region in 1991 and from integrating research to improve accounting for 5.7% of the total area cassava crop management, planted to cassava. Project activities processing, marketing, and consumer led to the rapid penetration of the preferences in the framework of Colombian animal feed market with cassava-based, development projects dried cassava chips. with strong farmer participation.
180
160 123456150
123456
123456
123456
140 123456
123456
123456
123456
123456
120 123456
123456
123456
123456 100 123456 123456
123456
123456 76 123456 80 123456 123456 123456 123456
123456 123456
123456 123456
123456 123456
60 123456 123456 46 12345650 123456 123456 1234567 123456 123456 123456
12345641 1234567 123456 123456 123456 40 12345637 123456 1234567 123456 123456 123456 123456 123456 1234567 123456 123456 123456
Cassava drying plants (no.) 123456 123456 1234567 123456 123456 123456 22 123456 123456 1234567 123456 123456 123456 123456 123456 123456 1234567 123456 123456 123456 20 123456 123456 123456 1234567 123456 123456 123456 8 123456 123456 123456 1234567 123456 123456 123456 1234568 1234567 123456 123456 123456 1234567 123456 123456 123456 1234561 123456 1234567 123456 123456 123456 1234567 123456 123456 123456 0 123456 123456 1234567 123456 123456 123456 1234567 123456 123456 123456 1981 82 83 84 85 86 87 88 89 90 Year
1234
1234 Figure 2. Adoption of cassava drying plants in Colombia, 1981-1990, by farmers’ groups (1234 ) and private plants ( ). (After Henry, 1992.)
339 Cassava Flour and Starch: Progress in Research and Development
Studies have also shown that organizational arrangements and adoption of cassava production allowing farmer organizations, technology components is significantly extension workers, and national higher in areas with ICRDP activities research and extension staff to play than it is in areas not so influenced new roles (CIAT, 1992). (Gottret and Henry, 1994). For example, 93% of cassava producers in The project in Ecuador was areas with cassava drying activities implemented in a traditional, and strong institutional presence cassava-processing area of Manabí adopted the cassava variety Province, a seasonally dry, coastal ‘Venezolana’ in 1991. But in areas not region, which accounts for 20%-30% directly influenced by ICRDP activities, of the national cassava production only 48% of cassava producers (MAG, 1990). In Manabí, family adopted it (Gottret and Henry, 1994). farming households have extracted cassava starch for over 100 years The main lesson of the Colombian with little change in processing project was that farmers, when technology. The potential of encouraged to participate in cassava-drying technologies had been researching and solving their current early identified as a viable alternative problems and needs, become for promoting alternative uses and important partners for research-and- markets for the crop. But it was not development institutions and make until 1985 that conditions became valuable contributions to identifying, economically favorable to launch the adapting, and evaluating alternative ICRDP in Manabí. solutions. A favorable climate for cassava The Colombian project also processing and sun drying, excess validated an original hypothesis of the cassava production, and a ICRDP model: that the integrated predominance of small-farm project approach, by creating new population characterized the region markets and better prices for cassava, as “optimal” for the project. will increase farmers’ incentives to Farmers were organized into small adopt improved production producer-processor associations technologies. called APPYs (Asociaciones de Productores y Procesadores de Yuca). Finally, the project demonstrated From the start, these associations that small-scale farmer associations joined, as a second-order farmer are indeed a viable mechanism or organization, known as the Unión de vehicle for technology diffusion. Asociaciones de Productores y Procesadores de Yuca (UAPPY).
The Ecuadorean ICRDP The UAPPY changed its legal status in 1992 to admit associations From its beginning in 1985, the of rural workers (ATAPYs) and Ecuadorean ICRDP represented a became the Unión de Asociaciones de challenge for CIAT in that the Trabajadores Agrícolas, Productores y Colombian project, successful as it Procesadores de Yuca (UATAPPY). had been, demanded very high This change allowed small-scale institutional costs, which had to be farmers, lacking titles to their lands, brought down. The project in Ecuador and landless rural workers (such as was therefore conceived as both a women who could easily benefit from social and technical experiment, processing-generated jobs) to legally requiring specific institutional and participate.
340 Integrated Cassava Research and Development Projects...
Begun as a marketing industry was such that demand for committee, the Union now includes cassava flour could be more than 17 associations and performs a variety 8,000 t/year. of functions including technical assistance, credit, marketing, Transforming dried cassava chips accounting, training, product to flour for shrimp feed required new development, and monitoring. steps in processing because roots had Farmers meet annually as to be peeled before drying. Peeling stockholders to evaluate their progress soon became an important source of and make recommendations to added income for member and UATAPPY leaders and other project nonmember families, especially collaborators. women, children, and elderly people, who usually had no other sources of Colombian farmer-processors were income. brought to Ecuador to teach Manabí farmers the new chipping and drying A different management system technology. These farmer-to-farmer was also needed, in which the contacts were later reinforced by associations produced dried chips and Manabí farmers visiting Colombia. sold them to the Union. The Union They were able to see in action was obliged to develop milling capacity technical, organizational, and and management, using portable operational features of the Colombian hammer mills to grind the dried chips cassava processing plants. From the into flour. This process catalyzed the start, farmer processors played idea of developing a Union-owned an important role as promoters, and administrated “Demonstration technology transfer agents, teachers, Center,” where new cassava and leaders of the project. Staff from processing technologies could be local agencies and CIAT joined and designed, adapted, and tested, and supported farmers’ efforts. training and demonstrations for farmers could be held. The basic chipping technology adopted was the same as that used In 1993, the Demonstration in Colombia. Drying trays, a Center became the “Central Plant”, CIAT-suggested technology, were reflecting its increasing roles in quickly adopted as an intermediate transformation, storage, and step toward building a cement drying transshipment activities. Training floor. This allowed poorer farmer and research activities were taken groups to get started quickly with over, to some extent, by specific fewer initial investment costs. Later, farmer associations, encouraging profits earned could be used to build increased participation. the floor. In 1989, the shrimp industry in Project leaders and CIAT Ecuador slumped: strong competition researchers assumed that the market from Asian producers and problems for dried cassava in Ecuador would be with a shortage of larvae ponds cut the same as that in Colombia: the shrimp production overnight, balanced feeds industry for poultry eliminating 95% of the demand for and livestock. Early in the project, cassava flour. The Union reacted serendipitously, it was discovered that quickly, launching an all-out cassava was an ideal substitute for campaign to identify other markets. imported chemical agglutinants for the The Demonstration Center made it feed pellets used by the Ecuadorean possible for farmers to rapidly adapt shrimp industry. The scale of this existing products for new markets.
341 Cassava Flour and Starch: Progress in Research and Development
For example, whole-root cassava than in number of processing flour was refined by passing it through organizations. Initially fueled by a mechanical vibrating sifter, a strong market demand and reasonable process yielding a flour of the same funding for construction and granular size as wheat flour. This operational credit, the processing refined cassava flour began associations’ expansion was very substituting wheat flour in fillers for rapid, from 2 in 1985 to 16 in 1988. resins used for making plywood, thus By the end of 1988, a scarcity of donor capturing an important share of this funds for construction and a rapidly market. Bran, a byproduct from increasing inflation combined to make sifting, was also sold as a source of promoting the formation of new fiber to livestock feed industries. associations much more difficult for the Union. In 1992, there were In 1989, farmers, collaborating 17 associations in Manabí, with a institutions, and CIAT learned a total of 320 members (Figure 3). valuable lesson about the importance of diversifying products and markets. The Ecuadorean ICRDP differed Since then, the Union’s markets and from other ICRDPs by having the products portfolio continued to UATAPPY as agent of its members’ diversify. Today, seven different growth and development. It has primary products and four byproducts managed and often carried out project are produced and sold to seven functions normally assigned to different market sectors (Table 2), supporting state institutions or reaching more than 40 buyers. nongovernmental organizations (NGOs), including handling The Ecuadorean cassava project’s development funds. This has served growth has been operational rather to strengthen and promote
Table 2. Market sectors and products in the Ecuadorean cassava project, 1989-1992.
Market sectors Products Total annual output (t)
1988/89 1989/90 1990/91 1991/92 1992/93
Shrimp feed and White industrial flour 574 982b 304b 631b exports to Colombia
Shrimp feeda Whole industrial flour 1,100 304 258b 464b 127b
Plywood industry Refined whole industrial 200b 170b 292b flour
Ice-cream cone Refined white food flour 33 6b 33b factories
Cardboard industry Industrial starch 70 188b 57b 256b (Ecuador and Colombia)
Bakeries, traditional Food starch 5 10 6b 9b 17b and large-scale
Livestock feed Starch bagasse and 24 103b 29b 166b flour bran
Total 1,105 1,015 1,743b 1,033b 1,522b a. After 1990/91, most of the “whole industrial flour” was used for other livestock feeds, and not shrimp pellets. b. Includes starches or “bagasse” purchased by the Unión de Asociaciones de Trabajadores Agrícolas, Productores y Procesadores de Yuca (UATAPPY) from private starch processors.
342 Integrated Cassava Research and Development Projects...
20 (3) Farmer organizations—not merely 12317 12317 123416 123416 123 123 receiving project benefits but 12341234123 123 15 12341234123 123 actively participating with farmers 12341234123 123 12341234123 123 “owning” their research agenda— 123410 12341234123 123 10 123412341234123 123 should be part of the institutional 123412341234123 123
123412341234123 123 Cassava strategy of an ICRDP. 123412341234123 123 5 12344 123412341234123 123 Collaboration between farmer 1234123412341234123 123 drying plants (no.) 12342 1234123412341234123 123 organizations and supporting 12341234123412341234123 123 0 12341234123412341234123 123 institutions in an ICRDP should be 1985 86 87 88 89 90 91 encouraged without creating Year relationships of dependence among Figure 3. Expansion of cassava-drying them. agroindustries in Ecuador, 1985-1991. The Brazilian ICRDP sustainability of the project after state institutions and NGOs withdrew their In 1989, the Kellogg Foundation support as funds run out. approved a 3-year grant (1989-1992) to CIAT and collaborating Brazilian Another difference has been the agricultural research and technical direct and active participation of assistance institutions and farmer women from the start in the Union organizations. The grant’s overall and in all project activities, as objective was to support the producers, processors, and managers. introduction of improved cassava Today, three kinds of processing production, processing technologies, associations exist: only men, only and appropriate organizational women, and mixed. Women comprise schemes for institutions and farmer nearly 33% of total membership. groups throughout the main cassava-growing areas of Ceará State, The UATAPPY experience with the Northeast Brazil. integrated cassava project over the past years has fully validated three In this region, an estimated guiding principles that can be 110,000 ha of cassava are harvested considered as part of the culture of the yearly with a total output of almost project’s participants and the criteria 1.2 million tons of cassava roots. For for their collaborating well: centuries, the main commercial outlet for production has been the casas de (1) The transfer of technologies is farinha. These are small communal more rapid, efficient, and effective processing units used to process when end-users are directly cassava roots into a toasted flour or involved and responsible. meal known as farinha de mandioca. (2) Farmers’ organizations are This flour is a staple product and effective intermediaries between source of income, especially in the farmers and institutions and can rural sectors of Northeast Brazil. be used as efficient channels for In Ceará State, an estimated project services, credit, and 14,000 casas de farinha produce information dissemination. A almost 200,000 t of cassava flour per farmers’ organization accumulates year, representing about 65% of the experiences and learning, thus state’s cassava production. contributing to the growth, maturity, and ultimate Northeast Brazil’s extremely sustainability of the farmers’ variable rainfall patterns cause wide group. fluctuations in cassava yields and so
343 Cassava Flour and Starch: Progress in Research and Development the supply and prices of farinha de project activity coordination and mandioca vary greatly. Because the integrate the research and extension main income of the region’s collaborating agencies in the project’s small-scale farmers derives from area of influence. cassava flour, this situation creates instability. Further, poor quality, the The project’s expansion, in terms small scale of operation, and of number of farmer groups organized, rudimentary cassava processing was explosive, mainly because technology further contribute to national and state government establishing commercial systems agencies strongly intervened to launch whereby farmer groups are forced to programs of financial aid in the form sell their product at low prices. of grants, thus allowing rural communities to build cassava drying The ICRDP’s strategy was to seek a agroindustries. From the 11 that had large, alternative, market that cassava already existed at the project’s start, could enter, especially in good rainfall the number of farmer groups rose to years when excess cassava production 158—about 75% were established usually means low prices. Once the during the project’s last year (1991) animal feed market was focused, a (Figure 4). pilot project was established to develop the local experience needed to The CCCs and RCCs played a strengthen local institutional capacity crucial role in the task of approaching for implementing cassava-based rural different government agencies and development programs with potential programs to obtain grants on behalf to benefit targeted groups. A of the farmer organizations. At the long-term objective was to develop same time, both these committees national capacity to carry out similar had permanent access to project development programs in other funds for assisting and supporting regions of Brazil. farmer activities. Despite the adverse economic situation the country Two factors significantly benefited faced during the project’s span, the the project: first, counterpart agencies committees were very active in in the State had previously worked on identifying sources of financial relating small-scale cassava farming support and channeling them toward and processing. And, second, the targeted groups. Project activities State’s institutional setup included top-level administrators, policy makers, and local agencies’ staff who 158 had been exposed to similar 160 1234 1234 experiences in other countries. Their 1234
1234 participation was fundamental in 120 1234
1234 defining the project’s organizational 1234
1234 and operational strategies. 80 1234
1234 Cassava 1234
123440 1234 40 A state cassava committee (CCC), 22 1234 1234 drying plants (no.) 11 12341234 1234 created before the project, was 12343 12343 1234 12341234 1234 0 123412341234 12341234 1234 strengthened and soon gained general 1986 87 88 89 90 91 recognition as the coordinating body ICRDP for project activities and all those Year related to promoting and developing the cassava crop in Ceará State. Figure 4. Expansion of cassava-drying agroindustries in Ceará, Brazil, Regional cassava committees (RCCs) 1986-1991. (ICRDP = integrated cassava were established to decentralize research and development project.)
344 Integrated Cassava Research and Development Projects... could therefore be executed within the With only 3 years of proposed goals. Total financial implementation, a complete ex post support from local agencies during evaluation of the project’s impact is the project’s 3 years was almost difficult. The speed with which 1 million American dollars (not cassava drying technologies are including local staff salaries). adapted for new regions and rural communities can be assessed through The project in Ceará followed an the pilot project’s monitoring and implementation model similar to that evaluation system model (involving of other ICRDPs, based mainly on base data on 133 cassava-processing transferring and adapting available farmer groups), a survey conducted at cassava processing technologies. This the beginning of the project, and took advantage of a strong extension another at its end. The assessment service that allowed rapid cover of the can be done in terms of increased region’s main cassava-growing areas. number of drying agroindustries and regions of influence, continuous Project activities also included increase in client numbers for dried some production technology research. cassava, and the degree of Initial results indicated that the strengthening of the organizational adoption of improved technology structure implemented for both components would help increase the institutions and farmer groups, which, region’s cassava productivity by as by the project’s end, included state much as 50%. However, these results and regional cassava committees and are suggestive only because farmers farmer organizations. did not have to pay the expenses. To what extent small-scale, A preliminary analysis of data poor-resource farmers would be from the two surveys indicates that willing to invest in, for example, on-farm consumption and use of organic fertilizers or weed control, cassava is changing. Farmers now sell remains to be assessed. a share of their production to the cassava drying agroindustries, in The relationship between farinha contrast with the situation before the de mandioca and dried cassava chips project, when the casas de farinha as the two main commercial options were the main commercial outlet. for cassava farmers in Ceará Farmers participating in the project determines the financial success of are starting to adopt the new the cassava drying agroindustries the processing technology. The new project promoted. When market market has stimulated them to prices for farinha de mandioca are transform their patterns of cassava low, the cassava drying plants use and become more market function efficiently as an alternative oriented. market. Conversely, when prices for farinha de mandioca are attractive, Qualitative information available then finding adequate supplies of raw on direct impact on community material for the cassava drying welfare, institutional support, and the agroindustries becomes difficult. general environment indicates that the pilot project served as a vehicle to Skewed land and farm-size increase community development in distribution, plus climatic general (organization, knowledge, fluctuations, also strongly influence employment opportunities, incomes), the seasonal availability of cassava and to strengthen local institutional roots and thus the performance of the support (technical assistance, working cassava processing units. capital). However, the project’s impact
345 Cassava Flour and Starch: Progress in Research and Development on cassava production and cassava-based farmer organizations. productivity was rendered negligible This last benefit is available only to because of the lack of opportunities organization members, whereas the for farmers to purchase or rent other three apply to any member of additional land. Adoption of improved the larger community within which production technology was slow the agroindustry operates. among the project’s beneficiaries. The total income of farmer The Ceará ICRDP proved that members of the Ceará cassava small, cassava-based, farmer processing groups during 1989-1992 organizations were attractive to reached US$163,887.00, of which cassava producers. These groups first 37.3% corresponded to cassava root had to improve their marketing sales, 10.0% to processing wages, and schemes. Early success indicates 52.7% to sharing annual profits potential for consolidation through (Figure 5). Another source of benefits stronger institutional commitment the project generated was captured by to support efforts by farmer nonmembers responsible for selling organizations. Those cassava-based 61.6% of the 7,080 t of cassava roots agroindustries able to operate during processed during the project. In the project helped create additional contrast, in the Ecuadorean project, employment opportunities, opened farmer members of the cassava-based alternative markets, stimulated local agroindustries earned, over 6 years, industry, raised farmer incomes, and an average annual income of US$225, encouraged overall community whereas nonmembers earned US$89 development. (Figure 6).
Funds are now being sought for Regarding direct economic a second phase: to consolidate the benefits, for the Colombian ICRDP, results obtained during the pilot almost 75% (US$16.2 million) of the project and to demonstrate these total project benefits was estimated to technologies and results to other accrue to cassava farmers (producers regions and farmer groups. and processors) (Gottret and Henry, 1994). But considerable indirect benefits have also been generated: Benefits and Beneficiaries backward linkages to several small of the ICRDPs industries supplying materials for constructing and operating the drying Benefits generated by the ICRDPs are plants; forward linkages include captured principally by farmer especially the income-generating effect members of the cassava-based from increased rural incomes. This agroindustries (Gottret and Henry, will have a multiplier effect in that 1994). Members can receive benefits increased rural demand for goods and from (1) a new market available for services will boost urban their cassava roots at more stable manufacturing. As such, rural prices; (2) more employment (and agroindustries have a strong, positive training) opportunities in the effect on overall economic cassava processing agroindustries; development. (3) value-adding second-rate cassava roots which previously had no market The ICRDPs also represent an value and were basically written off important source of benefits for before the introduction of cassava groups such as women and landless processing; and (4) the annual farmers, who usually do not benefit share of profits generated by the significantly from projects. For
346 Integrated Cassava Research and Development Projects...
200
123456163,887
123456
150 123456
123456
123456
123456 52.7% 95,277 100 123456 123456
123456 123456
123456 123456
123456789 123456 123456 10.0% 48,741 123456789 123456 123456 123456 50 123456789 123456789123456 123456 112345678234569
123456789 123456789 US$ (in thousands) 12345619,869 123456 123456 123456 123456789 123456789 123456789 37.3% 123456 123456 123456 123456 123456789 123456789 123456789 0 123456789123456 123456789123456 123456789123456 123456789123456 1989/90 1990/91 1991/92 Total 1989-1992 Year
123 Figure 5. Total 123incomes for cassava-processing group members, Ceará, 1989-1992. Sources of income
123 123
123 were = cassava sales; = processing wages;123 = annual profits.
400
321 123456
123456
300 123456
123456
123456 123456 225 123456 1234567
123456 1234567 200 123456 1234567 123456 1234567
123456 1234567 1234567133 123456 1234567 1234567 123456 1234567
1234567 123456 103 1234567 12345 12345 1234567 123456 1234567 89
1234567 123456 1234567 per farmer (US$) 100 1234575 12345 12345
1234567 123456 1234567 12345 12345 12345 1234567 123456 1234567
123456172345 12345162345 123456172345 Annual average income
1234567 123456 1234567 12345 12345 12345 0 1234567 123456 1234567 1985-88 1988-91 Total 1985-1991 Periods
1234 123
1234
123 Figure 6. Income earned by members (1234 ) and nonmembers ( ) of cassava-based agroindustries, Ecuador, 1985-1991. example, in the Ecuadorean project, strengthening of community spirit. US$15,000 was paid in 1990/91 for Increases in local income during the peeling cassava roots, 80% of which dry season resulted in increased went to poor, nonmember, women and purchases of foodstuffs and other items children who peeled cassava as their from local shops in rural communities, sole off-farm income. In the 1991/92 stimulating local economic growth. In processing season, this amount even some Manabí communities, the increased to 90%. In Ceará, Brazil, cassava-processing activity lessened the distribution of income earned by migration of men to other coastal farmers during the 3-year pilot project regions to work in the banana was 58.9% for smallholders, 32.4% for industry. The cassava-processing renters, and 8.7% for sharecroppers. infrastructure can be used for other commercial and cultural activities. For Other important benefits passed example, in Ecuador, cassava-drying to the community in which the patios are rented to dry other products cassava-based agroindustries (maize, castor beans, cocoa, rice). operated. Among these were easier Associations hold community fiestas, access to credit programs and charging entry to earn money. The training opportunities, integration drying patios make excellent dance of institutional presence, and floors!
347 Cassava Flour and Starch: Progress in Research and Development
In several communities, the Recommendations for cassava-based associations have Successfully Implementing motivated the creation of day-care ICRDPs (Lessons Learned) centers, and encouraged the building of roads and bridges, The ICRDPs now under way in several sponsored with government funds. Latin American countries have In Ceará, the wives of ICRDP provided a dynamic framework within members started small, poultry which CIAT’s Cassava Program has fattening operations beside the been interacting with various national cassava-drying floors to generate institutions, whether research- or complementary income. development-oriented, and with farmer groups. This interaction has made it easier to validate and adapt Types of Institutions existing production and postharvest and Their Functions in technology, together with the ICRDPs techniques developed for market analysis. Hopefully, these generalized The ICRDPs, in which different methodologies for implementing activities have to be developed ICRDPs will be adaptable to different simultaneously (e.g., production, economic conditions, farming processing, marketing, organization, systems, institutional capacities, and training, and monitoring), are markets. Based on the experiences integrated by nature. Because they that the Cassava Program has built are based on farmer organizations, up over the past years, some critical they generate demand for factors have been identified, which substantial resources and need to be addressed if ICRDPs are to coordinating mechanisms from other be successfully implemented. institutions. The organizational structure of any ICRDP must be Product and market development sufficiently flexible and adaptable to incorporate different farmer Until now, for marketing cassava organization schemes and roots, ICRDPs have depended on the institutional configurations. Table 3 traditional market (human shows the range of institutions consumption) and a new market currently participating in projects in (animal feed). Recently, they have Colombia, Ecuador, and Brazil and begun to diversify considerably, both the different functions each consolidating the markets for existing performs. cassava products and creating new products for new markets. This, in In Brazil, state institutions turn, has forced attention on played leading roles, while improving market financial second-order farmer organizations management and quality control. were slow to form. In contrast, in The long-term viability of the model Colombia, the second-order farmer depends on the farmer organizations’ organizations led the ability to move their products into a commercialization activities and wider range of markets or to develop some large-scale input buying. But a broader range of end uses for the few other activities, such as product, especially those that can research, were coordinated. In offer a high margin of profitability Ecuador, a wide range of institutions (added value). This not only applies played a multitude of roles, but the to cassava but also to other UATAPPY was the key player for commodities produced by farmer virtually all ICRDP functions. organizations.
348 Integrated Cassava Research and Development Projects...
Table 3. Types of organizations and their functions in integrated cassava research and development projects (ICRDPs).
Function of organization Region in countrya
North Coast Manabí Ceará (Colombia) (Ecuador) (Brazil)
Agricultural research ICA INIAP EMBRAPA EPACE Technical assistance ICA EMATERCE Rural development DRI FODERUMA SUDENE Credit Caja Agraria Banco Nordeste Farmer organizations: First order 180 groups 18 groups 165 groups Second order ASOCOSTA ANPPY UATAPPY COOPEMUBA COPROMA Nongovernmental FUNDIAGRO Esplar International CIAT ACDI USAID CIAT IBRD Kellogg Foundation Governmental: National Min. of Agriculture Min. of Agriculture Ministry of Agriculture Regional Sec. of Agriculture Sec. of Agriculture Sec. of Agriculture Sec. of Industry and Commerce a. Colombia: ICA = Instituto Colombiano Agropecuario; DRI = Fondo de Desarrollo Rural Integrado; ASOCOSTA = Asociación de Cooperativas de la Costa; ANPPY = Asociación Nacional de Productores y Procesadores de Yuca; FUNDIAGRO = Fundación para la Investigación y el Desarrollo de Tecnologías Apropiadas al Agro; ACDI = Agricultural Cooperative Development International. Ecuador: INIAP = Instituto Nacional de Investigaciones Agropecuarias; FODERUMA = Fondo para el Desarrollo Rural del Ministerio de Agricultura; UATAPPY = Unión de Asociaciones de Trabajadores Agrícolas, Productores y Procesadores de Yuca; USAID = United States Agency for International Development. Brazil: EMBRAPA = Empresa Brasileira de Pesquisa Agropecuária; EPACE = Empresa de Pesquisa Agropecuária do Ceará; EMATERCE = Empresa de Pesquisa, Assistência Técnica e Extensão Rural do Ceará; SUDENE = Superintendência do Desenvolvimento do Nordeste; COOPEMUBA = Cooperativa de Productores de Mandioca de Ubajara; COPROMA = Cooperativa de Productores de Mandioca de Açarau; IBRD = International Bank for Reconstruction and Development (the World Bank).
Crop production technology and strengthened. This requires research introducing adapted genetic materials, carefully exploring additional Developing and adopting cassava alternatives to maintain and enhance production systems that will sustain soil fertility, and adapting ecologically or increase productivity and reduce sound, crop protection practices. costs are critical to the ICRDPs’ success. For cassava to continue Sufficient evidence exists to prove competing, more intensive farm that small, cassava-based, farmer practices may have to be introduced, organizations can function as efficient thus risking increased pressure on the and effective enterprises and, as a natural resource base. Research and result, as vehicles for adapting and development on suitable production transferring production technology. systems must be initiated, continued, The challenge is to make them
349 Cassava Flour and Starch: Progress in Research and Development efficient and dynamic private sector range of services, from marketing, enterprises. through technical assistance, to applied research, and (2) represent Interinstitutional coordination their members in dialogue with other collaborating institutes or with Institutions. Interinstitutional government policy makers (creation of coordination is important to bring lobbying power). In Ecuador and, to a together the expertise needed to lesser extent, in Colombia, farmer support the farmer organizations in second-order organizations are playing the different areas and activities these roles and giving authority and handled by the ICRDPs. At their autonomy. inception, these projects involve diverse activities, beyond the scope of The interests of farmer, any single institution. The cooperative-based, agroindustries interinstitutional coordination must be reconciled with those of small mechanisms that an ICRDP requires or medium-sized entrepreneurial are usually new to local organizations, agroindustries. In the Colombian who will need an adjustment period to project, conflicts have already arisen. function appropriately and efficiently. To ensure smooth coordination, one The organizations, including institution should be designated as cooperatives and associations, need to “coordinator” among the rest, and be efficient, dynamic, and market sufficient funds should be allocated. oriented to be commercially successful. The social objectives of In summary, successful these groups are seen principally interinstitutional coordination must by the way profits are distributed. include at least (1) the identification Long-term sustainability depends of a coordinating institution, heavily on commercial survival. (2) agreement on the necessary functions of each participating institution, and (3) development of Human resource development coordinating mechanisms at project, regional, and national levels. Poor human resource development is a well-known constraint to the Farmer group, or organization, implementation of any rural program. or enterprise? Small, cassava-based, Training and networking are two organizations has proved attractive to important strategies to counteract it. cassava producers who rapidly build their organizations. But first-order Training. Establishing ICRDPs in farmer organizations are usually several Latin American countries has exceptionally weak in business highlighted the region’s deficiency in management and administration. institutions and personnel specialized Suitable instruments and in postharvest research and methodologies for improving these development, including marketing. skills are not always available, and if Thus, a great demand exists for they are, their use is often hindered by training research and extension very low levels of education. personnel and farmers in such areas as cassava processing, crop If the ICRDPs are to achieve management, basic accounting, autonomy in the medium term, then production technology, human and they must help form second-order financial resource management, farmer organizations that can marketing, market analysis, (1) support their members with a wide monitoring, and evaluation.
350 Integrated Cassava Research and Development Projects...
Experiences accumulated in having an explicit UATAPPY training various countries where ICRDPs have function. It designated a UATAPPY been implemented, especially Brazil member (farmer) to manage this and Colombia, show that training function and trained this person to activities have been mainly oriented carry it out in a highly professional toward building capacity among local manner. agency staff rather than among farmers, given the class structure and Networking. Forging links within organizational profile of their and among regions and countries is institutional environment. Ecuador one important aspect of implementing has been an exception to the ICRDPs. At a regional or national tendency: the UATAPPY and level, it is sometimes hard to achieve collaborating institutions carried out the interinstitutional and farmer training. Training strategies interdisciplinary approach needed to for technicians should link training translate new or improved production and work, using current and real and postharvest technologies into work-related problems as the training commercially viable activities. The issues, and work groups as the basic project framework, within which training unit. The sharing of training, ICRDPs are usually implemented, management, delivery, and facilitates integrating several national participation has resulted in greater institutions into a network that collaboration among partner provides a forum for interchanging institutions. experiences and methodologies and for resolving problems common across Educational and organizational regions and projects. needs of cassava producers are much greater than those of project staff. The Cassava Program at CIAT High rates of illiteracy and lack of and its partners in many national organizational skills (particularly institutions have developed those related to handling funds, methodologies over the last 12 years keeping records, organizing meetings) that have been operationally, are among the major constraints to economically, and technically viable. increased farmer participation in Regional and national networking ICRDPs and to a more efficient, seems to be the best way of ensuring two-way information flow between that accumulated experiences and them and project staff. knowledge can be made available to other regions and countries facing The current farmer-training similar problems and opportunities. strategies that local agencies and technicians use in most ICRDPs tend Monitoring and evaluation to include mainly formal training and mass communication activities Project monitoring and evaluation centered on extending technological (M&E) has been an integral part of the services rather than on training and ICRDPs’ methodology from the start. education. As such, these training Besides its use in defining potential methodologies tend to be useful only markets, research priorities and sites, for those farmers with the needed and beneficiaries, it has proved skills. This results in segregating the essential for short-term decision rest of the community, making it more making in refining specific objectives, difficult to develop a broader then undertaking appropriate actions. leadership base at the community level. The Ecuadorean ICRDP, During the early 1980s, an M&E however, tried to improve this by system was designed to be carried out
351 Cassava Flour and Starch: Progress in Research and Development at three levels, using different An improved model of M&E was methodologies: (1) continuous update developed for the Ecuadorean and of a database on farmer organizations; Brazilian projects. First, key to several (2) an annual survey of a large sample of the M&E limitations, was the model’s of collaborating farmers; and organizational structure and execution, (3) intensively monitoring a subsample which had to be based “in house.” That of farmers (Bode, 1991). is, the second-order farmer organization had to internally analyze the M&E For the first ICRDP in Colombia, system and coordinate its operation. the M&E system worked well in the Collaborating institutions should adopt beginning, but as the project matured, only technical assistance roles. An the database updating and subsequent effective feedback of appropriate annual reports based on its data information is thus delivered in timely became the only activities and outputs fashion to relevant audiences. of the M&E system, with much of the data underused. Furthermore, the Second, the M&E system should annual report was circulated to only a allow for the dynamics of the project few collaborating institutions, with itself. Parameters of interest during insufficient feedback to the farmer the project’s early stages may not be organizations themselves. The relevant for its expansion phases. monitoring model was seen as Adoption and impact studies need to suitable only for the pilot phase of a be included, but only at later stages. cassava-based development project, Different M&E activities thus become being too static to evolve with the important as the project matures project—different levels of project (Henry and Best, 1994). Table 4 shows maturity required different emphases how different monitoring activities are and aspects for M&E. introduced according to the project’s
Table 4. A modified monitoring and evaluation model for an integrated cassava research and development project.
Activity Sourcea Pilot stage Commercial stage Experimental Semicommercial
Short-term monitoring: Technical 1, 2 X X X Financial 1, 2 X X X Social 2 X X Commercial 2 X X X Institutional 2 X X Long-term monitoring: Markets 2, C X X Models 2, C X Adoption: Processing plants 2 X X Production technology 2, C X X Other technologies 2, C X X Impact: On-farm/processing plant 2, C X X Community C X Aggregate C X a. 1 = first-order farmer organizations; 2 = second-order; C = collaborators such as institutions, universities, and nongovernmental organizations.
SOURCE: Henry and Best, 1994.
352 Integrated Cassava Research and Development Projects... evolution. For example, market production credit. This has meant studies need to be conducted at the that traditional starchy staples, such experimental phase to suggest viable, as cassava, have had to compete with potential markets for the project. But grains at a substantial disadvantage. markets are dynamic so the market studies need to be repeated later to Exploiting postharvest ensure a sustainable market potential opportunities for root and tuber crops or, as in the case of the Ecuadorean is currently less of a technological experience, to look for product and problem, given the extensive expertise market diversification opportunities available. The central issue in (Brouwer, 1992; CENDES, 1993). developing cassava-based markets and products is the economics of the Another feature of the new M&E whole production and marketing model is that the intensiveness of data system. This is directly affected by collection diminishes as the speed of policy interventions oriented toward adoption increases. strengthening the bargaining power and the organizational levels of The new M&E model has already cassava producers. proved to be superior in that it is both more usefully effective and has In the Colombian project, policy increased efficiency in using resources issues were present from the very while contributing to the project’s start. The pilot project was begun in sustainability. In Colombia, for an area where an on-going land reform example, results of adoption and program was operating: farmers were impact studies have been fed back to receiving credit and technical research managers, scientists, assistance aimed at increasing second-order farmer organizations, cassava production in the region. policy makers, and donors for different Farmer organizations even had access specific uses. In Ecuador, more to credit for cassava production and market studies have been recently processing and for constructing conducted, which generated evidence processing infrastructure. The of potential demand for alternative Government controlled cereal imports cassava flour uses in nonconventional, and included dried cassava in the industrial products (CENDES, 1993). policy of minimum prices for In Brazil, cooperative-level processed agricultural products. This latter data have been fed back to farmer policy was first established, on a organizations within a month, six-monthly basis, in 1990 by the allowing them to assess their own Ministry of Agriculture. performance and relate it with that of other farmer groups. Policy issues became even more important during 1993/94 when Policy support and decisions decreased import duties (a result of Colombia’s economic aperture) allowed From their very inception, ICRDPs high-quality cassava pellets from have been closely related to and Indonesia to be imported at “dumping” affected by policy decisions and prices. This act set off a series of support. For example, all countries in high-level discussions that brought tropical Latin America are net together representatives of government importers of cereals and most research and extension institutes, the governments in the region have tried private sector, second-order to supply this increasing demand for cassava-processing organizations, carbohydrates through policy and CIAT. They then discussed the interventions and subsidized framework, individual responsibilities,
353 Cassava Flour and Starch: Progress in Research and Development and an action plan for a collaborative, any one cassava activity in isolation long-term effort to optimize the from the others. economic sustainability of the cassava sector in the North Coast in The ICRDPs provide an appropriate general and of the ICRDP in mechanism to bring together these particular. activities in a context where several kinds of institutions—including farmer In the Ecuadorean project, the organizations—can collaborate lack of government intervention to effectively. provide small-scale credit has been crucial in impeding the establishment For CIAT, as an international of cassava-based agroindustries, research center, the ICRDPs have preventing project activities provided a crucial testing-ground for expanding to other potential regions linking production and processing and cassava-producing areas. technologies, and for developing appropriate socioeconomic tools for In the Brazilian project, cassava market and monitoring research. The farmers benefited from policy feedback from the results has served decisions. Ten financial programs to shape priorities for future CIAT provided grants that helped establish research directions. To maintain cassava-processing plants. Two relevance to cassava farmer and credit programs for cassava processor needs, CIAT must preserve production and processing, based on strong links with ICRDPs activities and price variation of cassava products, an equally strong human and technical provided a certain stability of credit resource capacity in the areas of for farmers within the country’s production, postharvest, and highly unstable economic situation, socioeconomics. Partnerships and typified by inflation rates of 25%-30% collaborative arrangements between per month. CIAT and national entities are a must for future activities.
Conclusions Strengthening farmer organizations and their links to research and Three key conclusions result from the development are critical objectives for comparative analysis of the three the future. The ICRDPs offer both ICRDPs (North Coast region, international and national institutions Colombia; Manabí Province, Ecuador; a framework on which to build and Ceará State, Brazil). collaborative working arrangements with farmers through their (1) Integrating production, processing, organizations. and marketing research and development activities (2) Providing important social and economic benefits The ICRDPs clearly demonstrate that research and development must be The ICRPDs fulfill this role to holders integrated if the cassava crop’s full of small and medium-sized farms and potential is to be effectively realized. landless rural workers in marginal The intertwined relationships and farming sectors with few alternatives. dependencies of production, Cassava’s exceptional adaptability to processing, and marketing make it such marginal areas makes it a natural inefficient and illogical for indicator for poorer households and an institutions—whether national or appropriate vehicle for organizing international—to work exclusively on farm-level, income-generating,
354 Integrated Cassava Research and Development Projects... productive activities. The ICRDPs appropriate training materials. These, act as “magnets” for other types of in turn, will provide the vehicles by development efforts and can provide a which others will learn how to plan base to anchor and integrate these, and implement ICRDPs in other thus contributing to increased social cassava-producing regions in Latin stability and economic growth. America, Africa, and Asia. Concomitantly, such materials need (3) Farmer investment in improved to be dynamic, that is, created in a production technologies format that allows new lessons and experiences from more recent projects The ICRDPs have clearly proved that (on all three continents) to be assessed when increased value for the cassava and incorporated. crop is created through identifying new markets and developing new products Third, the ICRDPs would gain time to suit these markets, farmers will and reduce duplication of negative invest in improved production experiences through networking and technologies. Providing an appropriate exchanging visits between projects and incentive for farmers to invest in their through training and technical cassava production systems has assistance between technicians and profound implications for using new farmers. But no structure exists to technologies to increase productivity continue such exchange and and to induce resource sustainability. collaboration. Funding and leadership are needed to create this structure. CIAT could contribute significantly by Future Steps establishing norms for such interactions to take place. Looking beyond the immediate conclusions drawn from the ICRDPs’ Technology generated by public current experiences, one can see funds and agencies must remain freely several important tasks yet to be accessible in the public domain. At the accomplished. same time, private sector participation must be encouraged and its interests First, despite the many years of understood and accommodated in an collaboration between national equitable fashion. This will require programs in ICRDPs, there is relatively considerable international diplomacy little consolidation of the experiences and negotiation. and lessons learned from the individual projects, and what has been written is If a networking program is first not yet widely available for public use. placed within an existing, Most of the experiences remain lodged agroindustrial, regional network in the minds of practitioners who (e.g., Programa para el Desarrollo dedicated considerable portions of their Agroindustrial Rural [PRODAR] in professional careers to these projects. Latin America and the Caribbean), then CIAT must make a concerted effort to administrative costs would be reduced document these experiences, analyze and duplication of efforts prevented. the results, and make them available The ICRDP experience would be passed for wider consumption. to other productive sectors or commodities that could benefit from Second, there is a crucial need to this integrated approach. Likewise, the couple this documentation with ICRDPs would benefit from connections training programs that distill the to other possible agroindustrial ICRDP methodologies from case technologies that could diversify experiences, and transform them into current farmer organizations’ outputs.
355 Cassava Flour and Starch: Progress in Research and Development
Linking an ICRDP from Latin America References and the Caribbean region with those of similar interests in Africa and Asia may Bode, P. 1991. Monitoring and evaluation create further possibilities for internal systems for cassava drying projects. growth, lessen duplication, and reduce In: Pérez-Crespo, C. A. (ed.). Integrated cassava projects. technology development lag time. It Working document no. 78. Cassava could create greater horizontal Program, CIAT, Cali, Colombia. exchange across regions where similar p. 214-246. cassava problems and opportunities exist. These efforts may encourage Brouwer, R. 1992. The cassava flour demand in the plywood industry in farmer-to-farmer communication and Ecuador. Thesis research report. assistance across large distances and Department of Market Research, perhaps enable cassava development Agricultural University, Wageningen, to occur in areas where other, more the Netherlands. 108 p. costly, institutional efforts have failed. CENDES (Centro de Desarrollo). 1993. Estudio de mercado para conocer la Finally, because cassava is often demanda potencial de productores grown in marginal environments where elaborados de yuca. Unión de the resource base is rapidly being Asociaciones de Trabajadores degraded, ICRDPs offer an ideal Agrícolas, Productores y Procesadores de Yuca (UATAPPY) and CENDES, opportunity to explore with farmers the Quito, Ecuador. questions and problems of long-term sustainability for cassava-integrated CIAT. 1992. Cassava Program Report systems. Farmer-processors who have 1987-1991. Working document learned and earned the value that new no. 116. Cali, Colombia. 477 p. markets can give their cassava crops ______. 1993. Trends in CIAT have an incentive to conserve their commodities. Working document resource base and ensure that its no. 128. Cali, Colombia. productivity will endure. Such farmers p. 173-182. and their organizations can become Cock, J. H. and Lynam, J. K. 1990. Research willing collaborators in expanding the for development. In: Howeler, R. H. ICRDP’s focus to a landscape (ed.). Proceedings of the 8th perspective where the longer term Symposium of the International management of cassava is but one part Society for Tropical Root Crops of a complex resource management (ISTRC), Oct. 30-Nov. 5, 1988, Bangkok, Thailand. CIAT, Bangkok, system. Thailand. p. 109-119.
Mature ICRDPs must now turn Gottret, M. V. and Henry, G. 1994. La toward these more complex problems importancia de los estudios de and begin to focus attention on longer adopción e impacto: el caso del proyecto integrado de yuca en la term sustainability. Explicit attention Costa Norte de Colombia. In: Interfase must be directed to the systemic entre los programas de la yuca en impact of cassava production and Latinoamérica. Working document processing, including work on no. 138. CIAT, Cali, Colombia. productive capability, water and waste p. 193-223. management, and relationships with Henry, G. 1992. Adoption, modification and complementary and competing impact of cassava drying systems. If ICRDPs can indeed widen technology: the case of the Colombian their horizons and incorporate these North Coast. In: Scott, G. J.; issues and problems, then they may Ferguson, P. I.; and Herrera, J. E. (eds.). Product development for root achieve a long-term, positive impact on and tuber crops, vol. III. Centro the lives of rural people depending on Internacional de la Papa (CIP), Lima, cassava. Peru. p. 481-493.
356 Integrated Cassava Research and Development Projects...
______and Best, R. 1994. Impact of Lynam, J. K. 1978. Options for Latin American integrated cassava projects among countries in the development of small-scale farmers in selected Latin integrated cassava production American countries. In: Ofori, F. and programs. In: Fisk, E. K. (ed.). The Hahn, S. K. (eds.). Tropical root crops adaptation of traditional agriculture: in a developing economy: proceedings socioeconomic problems of of the Ninth Symposium of the urbanization. ANU Development International Society for Tropical Root Studies Centre monographs, no. 11. Crops (ISTRC), 20-26 October 1991, Australian National University, Accra, Ghana. ISTRC, Wageningen, the Canberra, A.C.T., Australia. Netherlands. p. 304-310. p. 213-250.
______; Izquierdo, D.; and Gottret, M. V. ______. 1987. Cassava consumption in 1994. Proyecto integrado de yuca en la evolution in Latin America: staple or Costa Atlántica de Colombia: Adopción vegetable. International Food Policy de tecnologia. Working document Research Institute (IFPRI), Washington, no. 139. CIAT, Cali, Colombia. DC. 38 p.
Janssen, W. 1986. La demanda de yuca seca MAG (Ministerio de Agricultura), Departamento en Colombia. In: Best, R. and Ospina, de Programación, Instituto Nacional de P. B. (eds.). El desarrollo agroindustrial Estadísticas y Censos. 1990. Encuesta del cultivo de la yuca en la Costa de superficie y producción por Atlántica de Colombia: Cuarto informe muestreos de áreas: Resultados de sobre las investigaciones realizadas en 1990, vol. 1. Portoviejo, Manabí, apoyo al establecimiento de las plantas Ecuador. de secado natural de yuca, período julio 1984-junio 1985. Proyecto Pérez-Crespo, C. A. (ed.). 1991. Integrated Cooperativo Fondo de Desarrollo Rural cassava projects. Working Integrado (DRI)-CIAT. CIAT, Cali, document no. 78. Cassava Program, Colombia. Vol. 2, p. 41-50. CIAT, Cali, Colombia. 242 p.
357 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 39
THE CASSAVA FLOUR PROJECT IN COLOMBIA: FROM OPPORTUNITY IDENTIFICATION TO MARKET DEVELOPMENT
Carlos F. Ostertag, L. Alonso, Rupert Best*, and C. C. Wheatley**
Abstract Product development concentrates on three main areas: The cassava flour project in Colombia first, the generation, evaluation, and began in 1984 with financing from selection of ideas for new products, the International Development in this case cassava based; second, Research Centre (IDRC). It seeks to the development of a product increase the income of small farmers prototype and process design, in cassava-growing areas by creating accompanied by industrial and/or an agroindustry focused on the consumer research; and, third, production of cassava flour for human product presentation, that is, quality and industrial consumption. specifications, product name, and packaging. The following discussion of the project “Production and marketing of The term “integrated cassava cassava flour in Colombia” outlines project” describes a rural the underlying methodological development strategy, executed in framework, and describes the project three phases by rural inhabitants, to activities executed during the promote the agroindustrial research, pilot project, and expansion transformation of cassava through phase. Emphasis is given to the pilot the integration of production, project. processing, and marketing functions and supported by governmental and nongovernmental organizations. Methodological Framework The research phase is in two The project uses integrated project parts: national analysis, in which the and product development national economy, the commercial methodologies. During the research outlook for cassava, and the stage, activities can be seen as potential of ideas for new belonging to one or the other cassava-based products are studied methodology (Figure 1), but as to select new products and a region. blending in the pilot project. In the second part—regional analysis—the selected region is studied in greater detail, especially regarding cassava production, farmer * Cassava Program, CIAT, Cali, Colombia. organizations, and nearby markets, ** Centro Internacional de la Papa (CIP), to select the best scenario for a pilot stationed at Bogor, Indonesia. project.
358 The Cassava Flour Project in Colombia:...
Phase
I Research Integrated project Product development
National analysis Ideas Regional analysis Research
Project design
II Pilot project Plant construction
Plant operation
Experimental Semicommercial
Test market
Feasibility study
III Expansion Expansion phase
Figure 1. Outline of the integrated project and product development methodologies.
During the second phase—pilot Colombia. The main use anticipated project—a pilot plant is established for cassava flour was in the and operated semicommercially under preparation of a wheat and cassava real market conditions to determine composite flour for bread making. the feasibility of the agroindustry. The region selected, the North In the final phase—expansion— Coast—also known as the Atlantic the processing units are replicated Coast—is the main cassava-producing and the market for the product is area in Colombia, with the root grown expanded to consolidate the new mostly by small-scale farmers. agroindustry. Accordingly, the economy of cassava production in the North Coast was studied, along with the wheat-milling Evolution of the Cassava and bread-making sectors. The Flour Project equipment for small-scale rural processing of cassava was adapted Research phase and developed. In addition, the influence of cassava varieties on the The objective of this first phase was to quality of cassava roots and derived determine the technical and economic products was examined. Surveys conditions required for developing the among consumers and bread makers cassava flour agroindustry in were conducted to evaluate the
359 Cassava Flour and Starch: Progress in Research and Development acceptability of breads made from 42 t of dried chips were produced and composite flours of wheat and transported by road to be milled in a cassava. commercial wheat mill in Medellín.
The research concluded that the An information system for development of a cassava flour production was developed and agroindustry was viable because implemented, and control parameters cassava flour could be sold at lower established. Specifications for the prices than wheat flour, and quality of raw material and sanitary consumers found the composite bread controls were drawn up. The acceptable. However, bakers saw a microbiological quality of the cassava high risk in lowering the quality of flour was monitored, and variable their products by using cassava flour. costs of production closely supervised. The decision was made to continue with the pilot project, on the Support research was conducted, understanding that alternative with the collaboration of the markets for cassava flour were Universidad del Valle (UNIVALLE) and identified. the Natural Resources Institute (NRI), UK. Areas investigated included the Pilot project phase improvement of processing equipment, control of microbiological In this phase a pilot cassava flour quality of cassava flour, development plant was set up and operated under of a small-scale milling system for real market conditions to assess the cassava chips, research on storage of feasibility of establishing the new cassava products, and development of agroindustry. The following activities moisture-measuring equipment for were carried out: cassava products.
Adjusting and evaluating Testing and demonstrating an production. A set of criteria (such as improved cassava production stability of farmer organizations or technology for the North Coast. performance of cassava crops) was Since 1989, 120 farmer-managed determined and used to select the site pre-production plots for for the pilot plant at Chinú, Córdoba. demonstration were established on The Cooperativa de Productores de los the North Coast with cassava-maize Algarrobos (COOPROALGA) was and cassava-maize-yam chosen as the executing farmer combinations; farmers were organization. The pilot plant was supervised by an agronomist. designed, and a local civil engineering firm built it within 3 months. Most of The recommended technologies, the equipment and machinery was which improved maize and cassava manufactured in a Cali workshop but yields, combined adjustments in the the metallic coal burner was available use of preemergent herbicides, commercially. A well was dug to fertilization of maize and yam, more supply the plant with water. intensive use of human labor, and use of improved maize varieties. Workers and administrative personnel were selected and trained. Identifying markets for cassava A daily and weekly timetable of flour and product promotion. As activities was drawn up and an described above, the focus on bread almost year-round supply of fresh making was modified after the cassava roots coordinated. In total, research phase. Market opportunities
360 The Cassava Flour Project in Colombia:... were sought in other food industry with a graphic design. The flour was categories where cassava flour would priced at 15% below wheat flour. have an equal or better functional advantage or where it could be Feasibility of the agroindustry: substituted, partially or completely, pilot project phase. A computerized for other flours or starches. financial model of the pilot plant was designed and updated periodically to A market study was conducted monitor production costs, plant nationally among food companies of efficiency, and profitability. At the different sizes. The study first end of the pilot project phase, the focused on products marketed and feasibility of the cassava flour raw materials; then, flour samples agroindustry was seen as follows: were distributed for substitution trials; and, finally, feedback was (1) Technical feasibility. The artificial obtained on the trials and buying drying process was inefficient; and intention was gauged. The study the microbiological quality of showed that potential markets for cassava flour was substandard. cassava flour included processed (2) Commercial feasibility. Additional meats, cookies, ice-cream cones, technical information was pasta, pastry, soup and sauce mixes. required. The physicochemical Cassava flour exhibits functional and microbiological qualities advantages in most of these products. needed improvement. More than 80% of the volume would (3) Cooperative-management be destined to replace wheat flour. feasibility. Sales and marketing Assuming that cassava flour could be personnel were needed to handle sold for 10% less than wheat flour product marketing. and that there would be adequate (4) Economic feasibility. The financial promotion, the estimated mid-term rate of return (FRR), a profitability market demand would be parameter, was calculated at 22%, 20,000 t/year. which was considered low.
The promotional effort Expansion phase concentrated on Medellín, which had milling facilities and the largest The project could not proceed with a single market detected in the study. formal expansion phase because of Sixteen firms were visited and given the constraints described above, but free samples of flour. The some action could be taken in subsequent trials were closely preparation for a future expansion. monitored. Inferences from this A hybrid pilot/expansion phase was experience were that the developed to convert the pilot plant microbiological quality was not into a commercial operation with acceptable to most companies, that improved profitability. the food industry was conservative, and that sales efforts would benefit Artificial drying costs were greatly from better technical information on reduced by doubling heat generation cassava flour. and switching from coke to mineral coal. This resulted in a shorter The flour developed was drying period and improved flour yellowish white and contained about microbiological quality. 80% starch. Its granule size was smaller than that of wheat flour. It The plant received a small was called “Yukaribe,” and packaged cassava-chip mill, developed jointly in polypropylene sacks, complete by CIAT and UNIVALLE. The mill
361 Cassava Flour and Starch: Progress in Research and Development consisted of a premilling component involved a team of architecture that reduced chip size and two students from UNIVALLE, supervised cylindrical screens that also by a member of the university staff. functioned as mills. The output was a first-grade flour (70%-85% Training materials, including extraction) and bran. In-plant milling videos and manuals on production reduced variable costs and and management, were developed. contributed toward satisfying local demand for the product. Feasibility of the agroindustry: expansion phase. By the end of Members of COOPROALGA, the 1993, the feasibility status of the farming cooperative managing the cassava flour agroindustry was seen pilot plant, were trained in the as follows: administration of small enterprises. (1) Technical feasibility. Food Developing and executing a industry: yeasts levels were too plan for expanding the cassava high. Adhesives industry: no flour agroindustry in Colombia. limitations. Cassava flour was promoted among (2) Commercial feasibility. Food the North Coast food industries, industry: additional technical especially meat-processing, cookies, information on cassava flour was and spices, with the eventual required by firms; physicochemical penetration of the meat-processing and microbiological quality sector. required improvement; cassava flour price is competitive against However, to increase sales further, wheat flour only in the North the marketing strategy was changed Coast. Adhesives industry: and cassava flour was promoted in additional technical information nonfood industries—especially was required by firms. adhesives and plywood—where (3) Cooperative-management microbiological quality was less feasibility. Food and adhesive important and higher market prices industries: sales and marketing could be obtained. Adhesive personnel were needed to handle companies in major Colombian cities product marketing. were provided with samples of (4) Economic feasibility. Food cassava flour and, simultaneously, industry: FRR was 26%. the Fundación para la Investigación y Adhesives industry: FRR was el Desarrollo de Tecnologías above 30%. Apropiadas al Agro (FUNDIAGRO) provided support in the development of cassava flour-based adhesives. The Conclusions adhesive markets in Cali and Barranquilla were penetrated, The major outputs of the cassava although industrial requirements flour project were: demanded increased flour purity by reducing the extraction rate during (1) The development of an efficient milling. small-scale system for cassava flour production. The design of the prototype (2) Although members of the building for the processing plant was executing cooperative had been revised to reduce costs and increase trained to manage the plant, a performance in accordance with the major priority was to improve the pilot project experience. Designing quality of the raw material used in
362 The Cassava Flour Project in Colombia:...
the plant, including industrial Ostertag, C. F. 1993. Plan de mercadeo para varieties. harina de yuca (July 1993-June (3) Project feasibility is uncertain, 1994). Working document. Utilization Section, Cassava Program, CIAT, Cali, because of high costs, deficient Colombia. supplies, poor quality of the region’s cassava roots, and ______and Wheatley, C. C. 1992. insufficient entrepreneurial Proyecto de producción y capacity of the executing comercialización de harina de yuca para consumo humano: Informe final, cooperative. Fase de proyecto piloto (junio 1989- (4) To plan successful rural diciembre 1991). CIAT, Universidad agroindustrial projects, the del Valle, and Fondo de Desarrollo following points must be Rural Integrado (DRI), Cali, Colombia. considered: ______and ______(eds.). 1993. Production and marketing of cassava (a) the importance of the flour in Colombia: expansion phase. integrated, or entrepreneurial, Annual report of a collaborative approach, encompassing project (Jan.-Dec. 1992). CIAT and interventions in production to Fondo de Desarrollo Rural Integrado (DRI), Cali, Colombia. 40 p. guarantee a sufficient supply of low-priced, quality raw ______and ______. (eds.). 1994. material; Producción y mercadeo de harina de (b) the need to assign enough yuca en Colombia: Fase de funds and time for product expansión. Annual report of a collaborative project (Jan.-Dec. 1993). development and marketing; CIAT, Universidad del Valle, and Fundación para la Investigación y el (c) the need to identify project Desarrollo de Tecnologías Apropiadas executors with entrepreneurial al Agro (FUNDIAGRO), and Fondo de abilities. Desarrollo Rural Integrado (DRI), Cali, Colombia. 41 p.
Bibliography
Best, R. and Ostertag, C. F. (eds.). 1988. The production and use of cassava flour for human consumption: research phase. Final report of a collaborative project (Oct. 1984-Oct. 1986). CIAT, Instituto de Investigaciones Tecnológicas (IIT), and the Universidad del Valle, Cali, Colombia. 85 p.
363 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 40
WOMEN AS PROCESSORS AND TRADERS OF CASSAVA FLOUR: THE PHILIPPINE EXPERIENCE
D. L. S. Tan, J. R. Roa, and E. A. Gundaya*
Abstract areas, which comprise about 15%-20% of land use in the Earlier surveys revealed that Philippines. About 500,000 cassava chipping is traditional small-scale and marginal farmers rely among women in Mabagon, a on root crops for food security and cassava-growing village in the supplementary cash income. Because Philippines. This paper discusses the the traditional ways of consuming experiences gained from the pilot root crops are few, optimizing their project conducted there to increase uses depends on an expanded the women’s processing efficiency by agroindustrial market. This means improving cassava chip and flour focusing on postproduction processing technologies and to assess technology. opportunities for market expansion. Studies in Asia and Africa have An association, consisting mostly shown that women farmers are largely of women (16 out of 19 members), was involved in postharvest activities, organized and trained to operate the particularly selling and processing. pilot plant and to promote and market Thus, the “Women in Postproduction the cassava flour produced. The pilot Systems” (WIPS) Project” was operation began in October, 1991. conceived to improve women’s The association now produces efficiency in postproduction activities 20-75 bags (at 20 kg/bag) of cassava and increase household incomes. flour per month. These are sold to This was first spearheaded by the nearby bakeries, which use the Southeast Asian Regional Center for cassava flour to prepare different Graduate Study and Research in baked goods. Plans for a full-scale Agriculture (SEARCA), collaborating commercial expansion are already with the Philippine Root Crop under way. Research and Training Center (PRCRTC), the National Postharvest Institute for Research and Extension Introduction (NAPHIRE), and the Isabela State University (ISU) for root crops, rice, Root crops are given high priority maize, and groundnuts. Funding because of their ubiquity in upland came from the International Development Research Centre (IDRC).
* Philippine Root Crop Research and Training Previous surveys in the Philippines Center (PRCRTC), Leyte, Philippines. showed that women are active as farm
364 Women as Processors and Traders of Cassava Flour:... helpers, sellers, and processors of Project Site and Beneficiaries root crops into native delicacies. An important finding was the indigenous The project site is Mabagon, a village processing of cassava into dried chips with a little more than 100 farming in the islands of Leyte, Bohol, and households, situated about 3 km to the Camotes, and Misamis Oriental the northeast of Hindang. Copra (from Province, for feed, food, and trade. coconut) and palay (from rice) are Women were largely involved. This the main agricultural products of finding provided an opportunity for Hindang’s hinterland, But most of intervention by the project. the lands planted to these crops are owned by a few, relatively rich, A diagnostic survey of root-crop landholders. farming households in Leyte Province, and an inventory of Small-scale farmers farm the possible technologies that could fit uplands, 70% of them owning the into local systems, helped develop the land they till. A transect showed a idea of introducing components of predominance of upland cultivation cassava flour technology (which uses of either sequential cropping or dried chips) to women farmers in the intercropping of cassava, sweetpotato, area around the town of Hindang, maize, vegetables (string beans, Leyte Province. The chips made in ampalaya, eggplant), and upland rice, this area are of relatively good quality with patches or fringes of taro and for flour. banana.
This paper serves as a Most men receive income by methodological note on the PRCRTC’s working as hired hands (planting, experience in cassava flour harvesting, threshing) in the rice fields, processing and commercialization, selling upland cash crops (such as root involving mostly women. This phase, crops, bananas, and vegetables), and which started in October, 1991, is an raising livestock. Most women are integral component of the WIPS engaged in selling various farm Project. products and processing cassava, on the farm, into dried chips for feed.
Objectives This mixed farming system, where indigenous cassava processing plays The project has the following an important role, was a promising objectives: match for village-based, cassava-flour processing and “shovel” feed mixing (1) To introduce root-crop equipment from byproducts. More especially, the that would improve the efficiency local system fitted the project’s of cassava flour processing in a particular concern for gender roles in selected community (i.e., farming systems and for improving Mabagon village near the town women’s cassava postproduction of Hindang, Leyte Province). activities. (2) To test storage technology for dried chips and flour. The Mabagon Root Crop (3) To strengthen the capability of Association (MARCA), the core beneficiaries in organizational group of collaborators, consisted of and entrepreneurial skills. 19 farmers and processors: 3 men and (4) To assess the effects of the 16 women. It was formed after several introduced technologies on consultations among the local people farming households. and was finalized during the general
365 Cassava Flour and Starch: Progress in Research and Development assembly in December, 1991. innovations unknown. The project Membership was voluntary; interest, was integrated in the sense that a commitment, and availability for the multidisciplinary team implemented it, groups’ activities were prerequisites. coordinating the phasing of various Currently, MARCA’s registration as a components, both technical and cooperative is in process, with all socioeconomic. requirements already met. This approach is characteristically systems-oriented, interdisciplinary, Technologies participatory, and oriented by users’ perspectives, local knowledge, The component technologies, pilot practices, and norms. tested for cassava flour processing, included: Project implementation involved carrying out activities of different (1) PRCRTC-developed,.village-level, components designed in a stepwise cassava flour processing machines but interphased manner to effectively (chippers, modified tapahan dryer, transfer the technology to a grinder, and flour finisher). functioning enterprise (Table 1). (2) Storage for chips. (3) Technology for byproduct use, that is, a neutral-scale “shovel” MARCA: Its Progress to Date technology, in which cassava meal is mixed with other ingredients to Registration produce a feed for swine. By consensus, MARCA was first In the initial phase of organized as an association and commercialization (toward the middle registered with the Department of of the second year), expansion of Labor and Employment (DOLE). This market uses was explored. This led to was partly because about half of the new food-processing products members, at first, resisted a technologies and, therefore, new cooperative registration, seeing a bakery products being introduced to conflict of interest with an already bakeries and to MARCA (e.g., cacharon existing cooperative in the village. [a puffed product with various flavors], Later, realizing the benefits of forming polvoron, and processing cassava a cooperative, particularly that of sticks and chips from fresh roots). obtaining funds, MARCA members voluntarily agreed to registration as a processing cooperative. Methodology With the registration, the The project took an integrated process cooperative met the requirements to approach, that is, a set of strategies receive support from the Countrywide was developed to coordinate needed Development Fund (CDF) for the components and was flexible enough processing facility. The registration to allow redesigning as new or and fulfillment of other requisites improved methods were tested, (including articles of cooperation, refined, and disseminated through the constitution and bylaws, seminar, and targeted beneficiaries. This approach economic survey) also brought support was essential for the project’s success from the Cooperative Development at the village level, where Authority (CDA). MARCA also received uncertainties were common and the assistance in registering with the reaction of people to introduced Department of Trade and Industry
366 Women as Processors and Traders of Cassava Flour:...
Table 1. Components and methods used for processing and commercialization of cassava flour to Mabagon village, Leyte Province, the Philippines, 1991.
Component Methods
Technical: Farmer-processors Training, processing trials (for both equipment and Informal team or group discussions processing) Feedback Participant observation
Bakers Training Baker-to-baker visits
Production: Study or field visits Farmers Farmer-to-farmer visits
Organizational buildup and Participant observation entrepreneurship development On-the-job training (e.g., in recording, inventory-taking, purchasing) Team buildup and group dynamics Specialized skills training (e.g., marketing, bookkeeping, accounting, and keeping financial records) Technical assistance (e.g., registration) Advisory discussions or consultations, formal meetings
Market development Market research (unstructured, use of checklist-users’ survey, feedback, contacting other markets) Researcher and farmer partnerships: (1) Expanding flour uses and testing markets (ready mixes with packaging and product testing) (2) Institutional collaboration for promotion (3) Byproduct use: coarse-grained flour in feed mix for swine (4) Integrated enterprise scheme
Monitoring and evaluation Informal group discussions, field visits, meetings (MARCA team, local advisory group) Workshops Resident research assistant’s logbook and diaries
(DTI), Bureau of Food and Drugs would condition individual members (BFAD), and a local nongovernmental toward effective group endeavor. The organization. remaining sessions concentrated on learning entrepreneurial skills, that Group buildup and entrepreneurial is, planning, organizing, operational development management, control, and evaluation. Building up entrepreneurial skills and strengthening the group were Specialized training in essential components for operational entrepreneurship. Sessions were sustainability. These were carried out given in collaboration with the DTI. through: An initial, one-day, entrepreneurial appreciation session was conducted Sessions on group dynamics. with emphasis on marketing skills. The first four sessions were designed Other sessions included bookkeeping to form values and attitudes that and marketing skills.
367 Cassava Flour and Starch: Progress in Research and Development
On-the-job training. During field Developing an integrated enterprise and monitoring visits, researchers gave informal consultations and discussions The viability of the cassava flour on business management, marketing, processing enterprise is expected to recording, inventory-taking, product evolve only gradually because of quality control, and equipment and competition from wheat flour and the facility maintenance. The resident lag involved in learning to use cassava research assistant gave a tutorial as flour. MARCA needed to engage in part of the post’s responsibility. enterprises related to its flour processing operations to solve liquidity Workshops. Two workshops were problems, improve income, and enhance conducted at the PRCRTC in August capacity as a market strategy. Thus, in 1992 and March 1993. They were 1993, the following operations were designed as learning exercises for integrated into MARCA’s business MARCA members in presentation and activities: analytical evaluation. The first workshop included MARCA and the Trading. MARCA buys fresh other agencies involved in the project. roots from farmers and sells them to a The second was an attempt by the starch plant situated about 80 km to PRCRTC to encourage the different the north. Trading is carried out from pilot project collaborators, and May to December when cassava drying governmental and nongovernmental is difficult because of the rainy season. agencies to interact and learn from Dried chips are bought during the dry each others’ experiences and to define season (January to April). Trading their respective roles in this and other starts in the last week of November. development programs. Operating a cooperative store to Changes in the operational scheme promote flour and feed. In November 1993, MARCA opened a village store Cassava flour processing follows a (Mabagon is strategically located, decentralized operation where roots are serving mountain barangays) to sell chipped and dried to a specified quality flour, feed, and other cassava-based by individual farmers, then sold to the food products. Noncassava feeds for plant. The chips are then milled and swine, such as the widely used base stored. MARCA distributes finished feed, were also sold to promote the flour on a per order basis, once a week. MARCA feed mix, which had a higher The schedule, organization, and protein content (14%-16% crude management of operational activities protein). were made according to the members’ time and ability. Market Development Several changes resulted from members’ experiences and feedback. Flour For example, the daily shift for a three-member processing team was The market target (25-30 bakeries, with changed because some members were a daily average total of eight bags, 10% unavailable for family and work cassava to wheat ratio) that would reasons. Starting January 1993, optimize plant use (4 t flour/month) MARCA hired a regular processor who was not reached within the first was paid P40.00 daily. The MARCA 6 months of operation. Only four members took turns in assisting the bakeries were regular users and eight regular processor. Each member was others were irregular, resulting in an paid P35.00 daily. average plant use rate of only 20%-30%.
368 Women as Processors and Traders of Cassava Flour:...
The reasons for the slow Twenty-five bakeries on Leyte Island penetration of the market were, first, were involved, from Maasin learning how to handle cassava flour (about 45 km to the south) to Ormoc dough requires time, if both owner (about 80 km north). Visits between and baker are interested. If the price bakers gave them a chance to incentive was too low or the learning exchange ideas and experiences, and time too long, owners and bakers were more effective in transferring lost interest. Second, the number of techniques and knowledge than was bakers trained unexpectedly fell training. Because of the peculiarities below target for the first 6 months. in handling cassava-wheat composite Third, the existing market used flour flour, further market expansion will at a lower rate than expected (i.e., take time, as more training and less than eight bags per day). exchanges are needed. Fourth, during the first year, the pilot project was still testing the Market survey. The main stability of chip and flour quality, as constraints remained the lack of well as test marketing, and an skills in using cassava flour for bread intensive marketing campaign was and the lack of price incentive. In not being pursued at the time. 1993, cassava flour sales declined by more than 50%. From the Given the results of this phase, informal market feedback, the the following marketing strategies nonsustainability of even the previous were undertaken: regular market may have been partly a result of the MARCA personnel’s Visits and training. inadequate marketing efforts Consultation workshops, (Figure 1). This meant that the baker-to-baker visits, and training trainees needed intensive exposure sessions were conducted to create and training during the remaining the market for cassava flour. months.
100
80
60
40 Number of bags
20
0 Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June 1992 1993
Figure 1. Sales of cassava flour in Mabagon village, Leyte Province, the Philippines, 1992/93.
369 Cassava Flour and Starch: Progress in Research and Development
Promotional posters for cassava concentrate on cacharon and polvoron. flour. Initially, 150 promotional The equipment is made and posters were produced with funding processing trials are expected to start from the PRCRTC’s extension during the first quarter of 1994. program. These are now distributed in Leyte and Samar Islands and Use of byproducts: cassava meal Surigao Provinces, and at the trade exhibits in the city of Cebu and at the Markets for cassava meal were Philippine Council for Agriculture and explored. The flour is made into a Resources Research and Development native delicacy (ira-id) but the market (PCARRD) at Los Baños (near Manila). is limited. About 2,000 kg of cassava meal were also sold to the ViSCA feed Testing other product ideas. mill at P3.50 per kg. But this market Mixes with cassava-wheat composite is unstable. flour were developed for the convenience food market. The A more promising venture is to use 500-g packages, with recipes and an cassava meal in swine feed mix. The improved packaging design, was ready ration was market tested in outlets in for promotion in November 1993. the nearby towns of Hindang and Hilongos. The formula contains about Other markets explored. A 15%-16% crude protein, as tested by distribution chain of native food the PRCRTC Laboratory. The price products, with 150 outlets throughout was competitive, being only about 72% the country and based in Manila, of that of the popular base feed for expressed interest in cassava flour. swine. Samples of cassava flour, cassava meal (2 grades), and dehydrated The MARCA feed mix is made from cassava gratings were sent for testing. pre-mix, and meals of cassava, fish, The cassava flour passed the quality copra, and ipil-ipil leaves. Local test but the texture needed to be finer, women and children supply the leaves to pass through a 60 mesh (down from (Table 2). Profitability ranged from the current 80). The dehydrated P0.50 to P0.75 per kg, depending on gratings were also acceptable and the the sources of protein used. Other firm is interested in placing an initial mix combinations, including kohol (a order. Grating equipment has been snail), will be tried out to determine installed for processing and marketing the most efficient mix. trials for the first quarter of 1994. The cassava meal was unacceptable for A plan is under way to promote ready mixes. the feed mix by integrating into MARCA’s operations the sale of Processing other food products complementary feeds, such as the from cassava flour swine base feed, which farmers commonly use. To expand the market for cassava flour, MARCA members were trained in food processing. Three training Machine Evaluation and sessions on various food products Improvement from cassava flour and fresh roots were conducted for MARCA members, Flour finisher one at Visayas State College of Agriculture (ViSCA) and two at the The first finisher brought to the site site. Because of a more promising was a manually operated machine market, MARCA decided to with a capacity of 20-40 kg/h when
370 Women as Processors and Traders of Cassava Flour:...
Table 2. Formula of a feed mix for swine, and costs. The mix was made by a cassava processing cooperative in Mabagon village, Leyte Province, the Philippines.
Ingredient or input Weight Crude protein content Cost (kg) (%) (P)
Cassava meal 52.10 1.0 208.40 Copra meal 24.00 5.3 120.00 Fish meal 9.00 5.4 90.50 Rice bran 8.50 1.0 25.50 Ipil-ipil leaf meal 4.15 0.9 12.45 Golden snail 1.50 0.3 6.00 Salt 0.50 2.50 Afsillin 0.25 29.00 Labor 30.00 Bags 6.00 Transport 10.00 Total 100.00 540.35 a a. Cost of feed mix per kilogram = P5.40; wholesale price = P6.50/kg; retail price = P7.00/kg.
tested at the PRCRTC. But when used members, having an estimated cost of by the farmer-operator, it did not P500. In contrast, the andolan—a perform as expected. The flour clogged local chipper made from a perforated the screen, barely flowing out of the GI sheet mounted on a piece of wood— finisher. This was withdrawn and a costs about P15.00 per unit. The temporary, manual one used until a chipper was therefore not cost effective new one was designed and made. for individual households, because of the very small scale of home Motor-operated, the new finisher processing. The portable chipper also had a fan which forced the fine flour to had to be mounted for the operator’s pass through the screen. This convenience. machine had a higher capacity than the old one: at least 50 kg/h in a single However, the expected advantages pass. The cooperative’s members used of the portable chipper are an it until another, improved, machine increased yield of chips and was made, based on farmer-operators’ eliminated risk of abraded hands evaluations. while processing. Cost-sharing among households may make the chipper The design now used has two main more cost attractive. improvements: the feeder hopper was enlarged to accommodate a larger flour Modified tapahan dryer volume, and a metering device was mounted. These modifications Dryers were used only during the improved the operation’s efficiency by rainy season, when sun drying was removing the tedium of manually impossible and orders for flour had to feeding and frequently stirring the be satisfied. ground chips in the hopper. They also reduced finishing time by about 50%. A dryer was constructed on site and tested. In the first two tests, it Portable chipper was too heavily loaded (463 and 200 kg of fresh chips), and the mixing A portable chipper introduced to the turned the chips brown and hence cooperative was expensive for the unsuitable for flour production. In the
371 Cassava Flour and Starch: Progress in Research and Development third test, the chips were not mixed Resident research assistant and their color was more acceptable for flour production. In the fourth Living in the village enabled the test, the farmers evaluated the dryer, resident research assistant to loading it with 190 kg of chips. The observe social behavior and norms. chips were not mixed, and dried in The assistant had to observe, about 12 h. Their color was lighter facilitate, train, and catalyze the than in the third test. farmers, and monitor results in logbooks or diaries. The assistant left the village in July 1993 as Improving Cassava farmers took over the flour Production Systems production project.
Although the issue of environment The local advisory group friendly cassava production on sloping land was raised during This interagency group consisted of informal discussions with farmers, it local government representatives, became a pressing concern with the DTI officer, a technician from the increasing commercialization. The Department of Agriculture, and issue of sustainability of cassava representatives from the village and production and processing systems the farmers’ group, MARCA, and the became integrated into the project. PRCRTC. The local advisory group was to build up local management Two groups of cassava farmers capability and to continue assisting from Hindang visited farming-system MARCA after the PRCRTC left projects in Matalom, where model Mabagon in March 1994. contour farms were shown. The farms had cropping systems similar Monitoring and evaluation to those of Mabagon and other cassava-producing communities. These were done, first, by the team, Farmers discussed the benefits based on observations from market of contour farming and the surveys, field visits, and notes and disadvantages of irresponsible feedback from the resident research farming. After two visits, seven model assistant; and, second, through contour farms were set up in MARCA’s regular monthly meetings, Hindang. These are still being and informal discussions with, and followed up. feedback from, MARCA. Farmer participation was always encouraged. Findings and Project Management: observations were used to plan, Monitoring and Evaluation modify, and improve the execution of activities. Interdisciplinary team approach
Active interaction among team Some Impact Indicators members was tried informally during field visits and discussions, and An important objective of the project formally through monthly meetings. was to assess the acceptability and Although the independent adoptability of introduced contribution of each discipline was technologies and their effects on valuable, team members were processing and on farming constrained by having other households (Table 3). responsibilities.
372 Women as Processors and Traders of Cassava Flour:...
Table 3. Acceptability and adoptability of introduced technologies for cassava flour production in Mabagon village, Leyte Province, the Philippines.
Technology Acceptability and/or adoptability
Machines:
Pedal-operated chipper Power efficient, acceptable, but of limited use. Most processors prefer the local andolan.
Grinder and finisher Acceptable, adopted. Easily learned. Modifications to enhance the grinding and finishing capacities.
Modified tapahan dryer Acceptable, but not adopted. Costly to use. Sun drying with plastic mats produces better quality flour more efficiently.
Portable chipper Initial testing. Not acceptable. Design being improved.
Bulk storage in Acceptable. Adopted. polyethylene bags
Processing:
Flour processing Adopted. Needs market expansion and promotion.
Swine feed mix Adopted. Needs market expansion and promotion.
Food processing: cakes, Accepted. Not adopted. No facilities, and difficulties in operation. doughnuts, siakoy.a
Cacharon.b Acceptable. Promising market. In the process of fabricating equipment.
Polvoron.a Acceptable. Adopted by individuals. Planned for enterprise. a. Editors’ note: No description of this product was provided by the authors. b. Cacharon is a puffed product with various flavors.
Organizing and entrepreneurial For the first 5 months of skills operation, at 30% capacity, the net profit per kg of fine flour was P0.61. Markedly satisfactory performance was With 90% capacity, this could observed in terms of growth in improve to P1.50/kg. If cassava cooperation, improved attitudes, meal is included, net profit per kg is processing skills, and enterprise 1.04 at 30% capacity and P1.79 at management. It was also evident in full (Table 4). Financial statements group work, attendance at meetings, (Jan.-Dec. 1992) show that, during assemblies, workshops, participation the year’s operation, profitability in discussions, and carrying out of decreased because plant use assigned responsibilities in operations dropped to 20% (see Appendix). The and marketing. enterprise’s profitability was improved with the use of cassava Enterprise diversification meal in feed mix. Profit per kg ranged from P0.50 to P1.10, MARCA is learning to integrate depending on the ingredients used, related enterprises to make operations which, in turn, were chosen so to more viable and profitable. An obtain a feed mix price that was “entrepreneurial” culture at the village P2.50 lower than the popular, base level is gradually evolving. feed brand.
373 Cassava Flour and Starch: Progress in Research and Development
Table 4. Cost and returns for cassava flour per month per capacity use in a flour plant at Mabagon village, Leyte Province, the Philippines. Assumptions were: fine flour yield = 85%; full capacity = optimal flour production for 120-h week; cost of chips = P4.00/kg; price of fine flour = P8.00/kg; price of cassava meal = P3.50/kg.
Cost and return per capacity use 1.2 t/month 4 t/month (15 bags/week) at (50 bags/week) at 30% capacity full capacity
Flour 9,600.00 32,000.00 (1,200 kg) (4,000 kg)
Less costs for: Chips 5,647.00 18,823.53 (1,411.75 kg) (4,705.88 kg)
Labor 1,577.45 3,154.90 Electricity 135.95 543.80 Marketing costs 271.60 1,086.40 Bags 300.00 1,000.00 Depreciation costs 937.00 1,405.50 Total costs 8,869.00 26,014.63
Net profit (fine flour) (per kg) 731.00 5,985.87 0.61 1.50
Cassava meal sales 741.16 2,470.58 (211.76 kg) (705.88 kg)
Total monthly income 1,472.16 8,456.45
Overall net profit per kg 1.04 1.79
Cost per kg of fine flour 7.39 6.50
Multiplier effect on the community Supplementary income via wage employment and other Market and income. From social benefits. Members derive January to December 1992, MARCA satisfaction from earning even a bought from the farmers a total of 20 t minimal wage by working at the of cassava chips, costing, in total, plant. They also feel a sense of P73,921.00. This contribution to achievement from learning new farmer income was substantial, skills and being active in an compared with the chips market enterprise—stimulated by before MARCA, in which only about motivation, pride, and hope that not 5 t/year were sold, assuming an all government projects fail. The average of 3.5 bags/week. Farmers in buildup of entrepreneurial spirit, Mabagon, Himacugo, Katipunan, and strengthening local institutions, and Baldoza are some of MARCA’s improvement in people’s suppliers. organizational performance and attitudes are benefits which are Improved chip quality. The difficult to measure. Yet they are quality (whiteness, aroma, and essential for rural mobilization and brittleness) of home-processed chips growth. The processing plant improved markedly, conforming to the became a source of prestige to the desired moisture content (12%-14%). community, and gave farmers Proof of this was that flour quality confidence that they could achieve stabilized. even more.
374 Women as Processors and Traders of Cassava Flour:...
Conclusions and intensifying the farmers’ Recommendations understanding of cassava flour use and market expansion. Currently, The approach commercial cassava flour production is not viable without This exploited the skills of, not only integrating the commercialization of different kinds of researchers, but byproducts, expanding end uses of also of the beneficiaries themselves. flour as, for example, a raw The participatory process eventually material in other products and food gave the farmer-processors a sense of processing, or trading related achievement: that through complementary products. To interactive, informal discussion with encourage farmers to set up a researchers they could make effective successful enterprise therefore decisions. Such “ownership” of requires a carefully integrated plan, achievement is key to the buildup of in which each step, made small, capacities, which can only be simple, and focused, is gradually achieved through gradual experiential introduced. The step-by-step learning. process would help farmers understand that every product or Local people’s involvement in additional activity needs a minimal project management also eased the standard of quality, stable task of team members who were supplies, good service, and constrained by time and competitiveness. resources. Local agencies shared responsibilities. Once the project A pilot and commercialization ends, their familiarity with it will project should therefore have the enable the locals to continue institutional or external support for managing the established enterprise. investment in market research and promotion because farmer groups Defining the focus and making usually do not have the needed the project small and simple funds to start up marketing intensified technology learning and activities. enabled the processors to stabilize product quality. Institutional flexibility
Participatory observation helped The research team members must discover social processes and be sensitive if they are to interrelationships, facilitating the successfully collaborate in modification or redesign of introduced arranging development activities in technologies. Behavior and attitudes such a way that the project has are central concerns in the process of technical, marketing, economic, technology transfer, preconditioning and operational viability. From the technology adoption. The project also beginning, team members must facilitated on-the-job learning of understand the need for such technical and entrepreneurial skills. sensitivity even in the planning Placing a qualified resident research process. The project’s success assistant in the field significantly depends on the ability of the team facilitated technology transfer. and farmers to respond to changes, and modify plans and strategies to Technology viability achieve objectives. Planning then becomes an iterative process. But The commercial viability of cassava being responsive to uncertainties flour processing depends largely on can be demanding on the team,
375 Cassava Flour and Starch: Progress in Research and Development which demands, if not addressed, Bibliography may cause delays or even failures. Buvinic,´ M. and Rekha, M. 1990. Women and This implies that some degree agricultural development. In: Eicher, of institutional flexibility is needed C. K. and Stratz, J. M. (eds.). Agricultural development in the Third in teaming up and distributing World. John Hopkins University Press, workloads to ensure that Baltimore, MD, USA. p. 290-308. researchers have adequate time to Cernea, M. M. 1991. Using knowledge from undertake the responsibilities social science in development projects. involved in a “commercialization” World Bank discussion papers, no. 114. project. These responsibilities are World Bank, Washington, DC, USA. based on the implications of the Pérez-Crespo, C. A. (ed.) 1991. Integrated integrated process approach: a cassava projects. Working document commitment to (1) using no. 78. Cassava Program, CIAT, Cali, participatory research methods, Colombia. 242 p. and (2) ensuring interactive Pretty, J. 1993. Participatory inquiry and learning between farmers and agricultural research. IIED researchers. Participatory Inquiry: notes for the 192A course. 16 p.
The integrated approach also Röling, N. Facilitating sustainable agriculture: assumes the availability of a turning policy models upside down. minimum, adequate, institutional IIED-PAP N92, version 2. International support to permit the exercise of Institute for Environment and Development (IIED), London, UK. the two basic responsibilities and provide the support services Sands, D. M. and Kaimowitz, D. 1990. The needed to make the project work. technology triangle: linking farmers, The policies of the participant technology transfer agents and agricultural researchers. International institutions should thus be geared Service for National Agricultural toward making the integrated Research (ISNAR), The Hague, the approach work. Netherlands.
376 Women as Processors and Traders of Cassava Flour:...
Appendix
Financial statements for the period January to December, 1992, of the Mabagon Root Crop Association (MARCA), a cassava processing cooperative at Mabagon village, near the town of Hindang, Leyte Province, the Philippines.
Statement A. Flour processing: the cost of goods manufactured (Jan.-Dec. 1992 operation)
Item P
Materials used Beginning raw material inventory (chips) 0 Plus purchases 73,921.00 Cost of raw material available for use 73,921.00 Less ending raw material inventory 1,196.00 Cost of raw material used 72,725.00 Plus other raw materials used (fresh roots) 2,720.00 Total cost of raw materials used 75,445.00 Direct labor 14,570.00 Factory overhead 12,816.05 Total manufacturing costs 102,831.95 Less cost of goods in process inventory 0 Cost of goods manufactured P102,831.95
Statement B. Flour processing: income statement for Jan.-Dec. 1992.
Item P
Sales Flour 98,930.25 Cassava meal 15,558.55 Damaged chips 1,365.50 Total sales 115,854.30 Cost of goods sold Beginning finished goods inventory 0 Cost of goods manufactured 102,831.95 Total costs of goods for sale 102,831.95 Less ending flour inventory 2,759.45 Cost of goods sold 100,072.50 Gross profit on sales 15,781.80 Less selling expenses Delivery personnel 900.00 Packaging 1,366.00 Transportation 3,983.00 6,249.00
Net income from operation P9,532.80
377 Cassava Flour and Starch: Progress in Research and Development
Statement C. Chips trading operation: income statement.
Item P
Sales 7,017.65 Cost of goods sold Beginning inventory (chips for feed) 0 Plus purchases 6,412.50 Cost of goods available for sale 6,412.50 Less ending inventory of chips 235.50 Cost of goods sold 6,177.00 Gross profit on sales 840.65 Less purchasing expenses 50.60
Net profit from operation P790.05
Statement D. Balance sheet: feed mix operation at end of December 1992.
Item P
Assets Cash 533.45 Accounts receivable 1,542.25 Inventory 1,471.30
Total assets 3,547.00 Liability Accumulated profit 3,547.00
378 Women as Processors and Traders of Cassava Flour:...
Statement E. MARCA balance sheet for the year ending December 1992.
Item P
Assets Cash Flour and chips operation 11,206.20 Feed mix operation 533.45 Registration fees 340.00 Chipper rent collection 130.15 Bank account 33,437.15 Accounts receivable Flour and chips operation 2,031.50 Feed mix operation 1,542.25 Inventory Flour and chips operation 4,190.95 Feed mix operation 1,471.30
Supplies and materials purchased Drying mats 950.00 Fluorescent tube 152.00
Buildings and warehouse 10,434.10 Electricity installation 333.65 Processing machines 50,958.65
Total assets 117,711.35
Liabilities Accounts payable 789.75 Accumulated depreciation 9,843.75 Loans: SEARCAa 5,000.00 Others 23,497.60 Processing machines 50,958.65 Owners’ equity Labor capital raised 14,559.25 Profit from operation 13,869.85
Less bank charges 75.00 Wall clock 189.50 Registration expenses 93.00 Drying mats 450.00
-807.50
Total liability and owners’ equity 117,711.35
a. SEARCA = Southeast Asian Regional Center for Graduate Study and Research in Agriculture.
379 Cassava Flour and Starch: Progress in Research and Development
CHAPTER 41
DEVELOPING THE CASSAVA FLOUR INDUSTRY IN RURAL AREAS OF INDONESIA
A. Setyono*, Sutrisno*, and D. S. Damardjati**
Abstract second was at the farmer group level, where farmers worked together to Increasing cassava production and produce cassava flour, market it, and developing the technology for cassava process and market flour-based processing involve tackling problems products. The third was at the in such areas as technology, cooperative level, where the productivity, marketing price cooperative village unit (Koperasi Unit stability, and production continuity. Desa) collects cassava flour from Once harvested, cassava is farmers and farmer groups, and then perishable, that is, the roots are of sells it to the retail trade and food acceptable quality for only a few days, industry, the feed industry, and other creating a major problem for farmers consumers. who are thus in a low bargaining position. Cassava flour is one way of Results indicated that marketing overcoming this problem. was a major problem in Central Java’s cassava flour industry. This study aims to (1) develop the Cassava flour use and its processing cassava flour industry at three levels, technology have not yet developed. (2) increase cassava’s added value The cassava flour industry has little and thus farmer income, and knowledge of and experience with (3) develop this industry in rural marketing, which hinders areas. development. The industry can be developed in rural areas only through Three levels of development of the the cooperative system, or the farmer cassava flour industry were attempted group system, if given support in in rural areas. The first was at the developing processing technology and level of the individual farmer, where household industry, and in obtaining farmers’ activities included cassava processing equipment and machinery. flour production, marketing of cassava flour, and processing and marketing flour-based products. The Introduction
Cassava (Manihot esculenta Crantz) is the most important staple food crop after rice and maize in Indonesia. At * Sukamandi Research Institute for Food Crops, West Java, Indonesia. present, farmers cultivate cassava in ** Bogor Research Institute for Food Crops almost all areas of Indonesia, from (BORIF), Bogor, Indonesia. lowlands to highlands, in dry or wet
380 Developing the Cassava Flour Industry in Rural Areas... climates, and under various soil Thirteen of Indonesia’s provinces conditions. Table 1 summarizes the (Table 3) are major cassava-producing use of upland areas in Indonesia. areas, each province having more Wargiono (1988) stated that the than 10,000 ha under cassava harvested area of cassava in (Pabindru, 1989). The average yield Indonesia showed a decreasing trend per ha is low at 10-12 t/ha. This can of 0.7% per year. But since 1986, the be increased by introducing new trend has increased slightly and, in technologies to farmers such as 1991, the total harvested area was improved varieties and cultural about 1.3 million hectares, with a practices. On a cassava estate owned total production of almost 16 million by a tapioca factory in Lampung, tons (Table 2). Cassava’s production yields of 25-30 t/ha have been rate from 1969 to 1985 was 2.05% continuously achieved (Rusastra, per year (Affandi, 1986). 1988).
Table 1. Summary of use of upland areas (ha) in Indonesia, 1984-1987.
Kind of upland Year
1984 1985 1986 1987
Cultivated (permanent basis) 8,327,282 8,091,282 8,377,480 8,761,476
Cultivated (temporary basis) 2,950,485 2,826,683 2,902,528 3,125,278
Unused or uncultivated 7,371,511 7,409,646 8,097,646 8,320,418
Total 18,649,278 18,327,611 19,377,654 20,207,172
SOURCE: SFCDP, 1990.
Table 2. Harvested area, production, and Table 3. Production and yield per hectare in yield rate of cassava in Indonesia, cassava-producing provinces of 1984-1992. Indonesia, 1991.
Year Harvested Production Yield rate No. Province Production Yield rate area (000 t) (t/ha) (000 t) (t/ha) (000 ha) 1. North Sumatra 337.7 12.4 1984 1,350 14,167 10.5 2. South Sumatra 407.8 12.2 3. Lampung 1,828.2 12.7 1985 1,292 14,057 10.9 4. West Java 2,129.0 13.3 1986 1,170 13,312 11.4 5. Central Java 3,313.4 12.1 1987 1,222 14,356 11.7 6. Yogyakarta 680.7 11.3 1988 1,302 15,471 11.9 7. West Java 3,718.2 12.6 8. Bali 260.5 13.5 1989 1,408 17,117 12.2 9. Maluku 223.9 10.8 1990 1,312 15,830 12.1 10. Northern Territory 763.3 10.3 1991 1,319 15,955 12.1 11. West Kalimantan 264.1 9.9 12. South Sulawesi 483.1 11.6 1992a 828 10,221 12.3 13. Southeast Sulawesi 996.7 11.3 a. Preliminary data. SOURCE: CBS, 1991. SOURCE: CBS, 1992.
381 Cassava Flour and Starch: Progress in Research and Development
Problems of Developing the Java sell about 50% to 90% of their Cassava Agroindustry fresh cassava roots to traders or middlemen. These are cassava’s association with low social status; inadequate Farmgate prices of cassava marketing, postharvest handling, fluctuate between Rp (rupiahs) 26 processing, and cultural practices; and Rp 177/kg, according to location and low productivity. and harvesting time (Tjahjadi, 1989). Cassava is also perishable, and often Association with social status cannot be processed or consumed immediately after harvest. These Most Indonesians consider cassava as problems limit the flexibility of a food for those of low socioeconomic cassava and force farmers into a low status. When income increases, then bargaining position. consumers switch from cassava to rice. Cassava consumption per capita Postharvest handling and per year has tended to decrease processing gradually in Indonesia, dropping from 57.4 kg per capita in 1983, through Cassava is usually harvested 51.0 kg per capita in 1988, to 43.1 kg manually, and may suffer severe per capita in 1990 (Table 4). damage if the roots are not carefully dug out of the ground. Roots Marketing deteriorate rapidly after harvest, and are bulky, making transportation Most cassava in Java is used for difficult and expensive. human consumption or starch (tapioca). Cassava farmers near According to the Indonesian food starch factories usually sell fresh balance sheet data (CBS, 1992), total roots directly to the factories, while cassava production in 1991 was those in remote areas tend to first 15.8 million tons (Table 5). Of this, process cassava into gaplek, or dried 56.0% was consumed fresh or as cassava chips, and then sell to gaplek; 15.7% was exported as gaplek middlemen, who transport and sell (chips), pellets, and tapioca; and the chips to exporters or pelleting 20.3% was used as raw material in factories in urban areas. Farmers in industries such as tapioca (starch)
Table 4. Average per capita consumption of major food crops in Indonesia, 1983-1990.
Commodity Per capita annual consumption (kg)a
1983 1986 1988 1989 1990 1991
Rice 145.21 147.36 150.18 140.84 150.05 145.53 Cassava 57.41 51.49 51.00 51.41 43.07 48.87 Tapioca 0.50 1.35 1.00 - - - Gaplekb - - 1.46 - - - Sweetpotato 12.46 11.05 10.93 11.04 9.74 9.61 Wheat 8.19 5.96 6.59 6.93 7.54 7.71 Maize 27.35 29.25 30.75 26.81 29.68 28.73 Soybean 4.45 8.80 9.49 8.80 10.72 11.01 a. - = data not available. b. Gaplek = dried cassava chips.
SOURCES: CBS, 1991; 1992.
382 Developing the Cassava Flour Industry in Rural Areas...
Table 5. Trends in production and use of cassava in Indonesia, 1987-1991. No data were available for exports or nonfood industries. (Values in parentheses refer to percentages rounded off.)
Production or use Fresh roots (or equivalent) (thousands of tons)
1987 1988 1989 1990 1991
Total production 14,356 15,471 17,117 15,830 15,813 Waste 1,866 (13) 2,011 (13) 2,225 (13) 2,058 (13) 2,056 (13) Manufactured for: Feed 287 (2) 309 (2) 317 (2) 317 (2) 316 (2) Food industry 3,401 (24) 4,288 (28) 5,781 (37) 5,781 (37) 4,583 (29) Food consumption 8,802 (61) 8,863 (57) 7,674 (48) 7,674 (48) 8,858 (56)
SOURCES: CBS, 1989; 1991; CBS, 1990, personal communication.
(7.9%) manufacture and nonfood farmers, (2) introduce and develop industries (12.4%). Postharvest cassava flour production and the losses are relatively high, about processing of flour into other 13.0%. products, and (3) develop household and small-scale cassava processing Cassava roots can be used in industries in a village of Central various forms: fresh roots are cooked Java. (boiled, roasted, steamed, or fried); fermented to produce tape; dried (either whole root, slices, or chips) Materials and Methods to produce gaplek; extracted to produce tapioca (starch); or the Research took place in Kejobong gaplek milled to produce flour. Subdistrict, Purbalingga District, Gaplek can be kept as a food reserve Central Java Province, during or as animal feed. In villages of Java, 1991-1993. It was conducted in most cassava is used for human three phases: surveying, introducing consumption, and many traditional cassava flour production and products are produced for local and processing technology, and evaluating national consumption. the development of the cassava flour industry. Cassava as a marginal crop Surveying cassava postharvest Farmers tend to grow cassava with handling and processing traditional, sometimes inadequate, technology. Being a crop with A survey was carried out in unstable prices (a consequence of Purbalingga District, from May to undeveloped processing technology), June 1991. Primary data was cassava is often grown in fragile soils collected from farmers on how they with little or no investment in handled cassava after harvest, fertilization. processed the roots, and marketed their products. A literature search was also conducted on cassava Study Objectives production, area of land use, and cassava processing in Purbalingga Our study aimed to (1) improve District. From all these data, we postharvest handling of cassava by chose the experimental site.
383 Cassava Flour and Starch: Progress in Research and Development
Introducing cassava flour Results and Discussion production and processing technology Survey results
The second phase, that of Socioeconomic conditions of introducing new cassava flour Kejobong Subdistrict. Table 6 production technology and summarizes land use in Purbalingga processing, was conducted from District. Land use in Kejobong August 1991 to March 1992. Subdistrict is divided as uplands (about 84%), lowlands (4%), and Evaluating the development of the degraded lands (12%) (Table 7). cassava flour industry Altitudes range from 70 to 100 m above sea level, climate is type A, and The development of the cassava annual rainfall is 4,048 mm (Table 8). flour industry in Kejobong Subdistrict was evaluated during Total population in Kejobong June to September 1993. The Subdistrict was 66,712 (32,622 males evaluations were at individual, and 34,049 females). Most people in group, and cooperative levels in Kejobong derived their income from rural areas, including cassava flour agriculture: 40% from food crops, entrepreneurs. Production, fishery, and cattle raising; and 4% processing, marketing, and other from other agricultural work. The problems were also assessed. rest worked in industry (7%); retail
Table 6. Summary of land use (ha), by subdistrict, in Purbalingga District, Central Java, Indonesia, 1983.
Subdistrict Lowlands Uplands Degraded lands Total
Bukateja 2,103 2,137 - 4,240 Kejobong 361 7,811 1,090 9,262 Kaligondang 1,121 3,932 1,212 6,265 Kemangkon 2,311 2,203 - 4,514 Purbalingga 798 676 - 1,474 Kalimanah 2,928 1,049 - 3,977 Kutasari 2,377 5,833 310 8,520 Bobotsari 1,275 1,953 311 3,539 Mrebet 1,607 3,182 924 5,713 Karangrejo 1,295 10,785 795 12,875 Karanganyar 2,414 4,422 290 7,126 Karangmoncol 1,609 4,419 1,068 7,096 Rembang 2,007 7,152 3,372 12,531
Total 22,204 55,554 9,372 87,130 Percentagea 25 64 11 100 a. Values are rounded off.
384 Developing the Cassava Flour Industry in Rural Areas...
Table 7. Summary of land use in Kejobong Subdistrict, Central Java, Indonesia, 1983.
Type of land use Area
(ha) (%)a
Lowlands: Technical 166 2 Semitechnical 31 <1 Simple 16 <1 Rainfed 148 2 Total 361
Uplands: Building and garden 3,224 35 Cultivated (temporary basis) 4,332 48 Other 225 3 Total 7,781
Degraded lands 1,090 12 Overall total 9,232 a. Values are rounded off.
Table 8. Monthly rainfall and number of rainy Harvesting, and postharvest days per month, averaged over 9 years, handling and processing Purbalingga District, Central Java, Indonesia, 1981-1989. Harvesting. Two major varieties Month Monthly rainfall Number of rainy of cassava are planted in Kejobong: (mm) days per month the bitter ‘Klanting’ (90%) and the sweet ‘Darme’ (10%). Harvesting is January 481 19 usually by hand during August to February 484 20 March 436 19 November. Of 36 respondents in April 418 19 seven villages, 7 harvested the May 236 12 cassava themselves, 6 paid others to June 181 10 harvest, 4 harvested through the July 137 8 cooperative system, 17 had sold the August 105 7 harvest in advance, and 2 did not September 256 11 harvest. October 336 15 November 493 18 Postharvest handling and December 483 20 processing. Postharvest handling and processing of cassava have not Total 4,046 178 Av./month 337 15 yet developed in Kejobong, because most farmers sell cassava as fresh roots. Only about 30% of farmers process cassava, producing such traditional goods as gaplek, tiwul, and (4%); transport (<1%); government cantir. Only 5% of farmer-processors (1%); and others (<1%). About 2% of produced tapioca (Table 11). employed were not reported (Table 9). The farmers either sold peeled Kejobong is the major center of cassava to middlemen (50%) and cassava production in Purbalingga retailers (8%), or were paid in advance District. Production was 43,671 t in before harvest (42%). Because the 1986 (Table 10). total potential capacity of factories
385 Cassava Flour and Starch: Progress in Research and Development
Table 9. Population by livelihood, Kejobong Subdistrict, Central Java, Indonesia, 1986.
Source of livelihood People Remarks
(no.) (%)a
Agriculture: Food crops, fishery, and cattle raising 26,614 40 Other agricultural work 2,392 4 Agricultural laborer Industry and Services 4,995 7 Entrepreneur or employer Retail trade 2,895 4 Transportation 133 <1 Government 814 1 Functionary, laborer, army worker, pensioner Others 378 <1 Unreported 1,538 2
Total employed 39,759 60 Total population 66,712
a. Values are rounded off.
Table 10. Total production (t) of food crops in Purbalingga District, Central Java, Indonesia, 1986.
Subdistrict Lowland Upland Maize Soybeans Groundnuts Sweet- Cassava rice rice potato
Bukateja 18,023 17 133 151 221 - 2,047 Kejobong 2,604 2,134 14,435 67 239 - 43,671 Kaligondang 7,810 - 925 143 221 - 4,513 Kemangkon 23,850 1,082 1,898 426 256 34 970 Purbalingga 8,118 - 226 79 103 - 34 Kalimanah 28,694 - 921 285 241 29 21 Kutasari 16,046 1,931 6,805 143 672 714 5,657 Bobotsari 8,958 - 1,636 106 35 126 1,223 Mrebet 15,670 - 1,285 142 263 49 1,824 Karangrejo 3,073 - 2,357 130 - 435 3,244 Karanganyar 19,281 385 1,092 96 - 53 3,044 Karangmoncol 5,095 - 226 53 - - 176 Rembang 9,804 91 1,052 80 3 224 5,422
Total 167,026 5,640 32,991 1,901 2,254 1,664 71,846
Table 11. Percentage (values rounded off) of was equivalent to 12,092 t of fresh respondents (farmers) who process cassava (i.e., 2,423 t of tapioca) cassava, and their products, Kejobong Subdistrict, Central Java, Indonesia. (Table 12), the total cassava production of 71,846 t could not be Product Respondents processed. Consequently, cassava prices fell, fluctuating according to Gaplek (dried cassava chips) 17 Cantira 8 retailer or tapioca factory. In 1989, Cendola 3 the price of cassava ranged from Tiwula 3 Rp 25 to Rp 30/kg. Tapioca 5 Cassava flour 0 But after cassava flour processing Total 31 was introduced, the price of cassava rose from Rp 50-60/kg in 1990 to a a. Editors’ note: No description of this product was peak in 1991 and 1992 at Rp 90-115, provided by the authors.
386 Developing the Cassava Flour Industry in Rural Areas...
Table 12. The capacity of tapioca factories in Purbalingga District, Central Java, Indonesia, 1989.
Manufacturer Subdistrict Started Potential Operational operations capacity capacity (t/year) (t/year)
Lamuk Kejobong 1983 8 8 Pandansari Kejobong 1987 75 60 Wanakusuma Kejobong 1988 720 600 Sribumikarya Kemangkon 1988 720 600 Tridaya Bukatiga 1988 900 900
Total 2,423 2,168
and dropped slightly to Rp 70-80 in Cassava Flour Production 1993. Two years ago (i.e., 1991/92), and Processing the production of cassava flour was Development not profitable, because the cassava flour price ranged from Rp 350 to The objectives of this development Rp 400/kg. project were to (1) encourage the production and processing of Cassava flour production cassava flour by individual involves several processing steps: farmers and farmer groups, and peeling, washing, slicing or rasping (2) increase the added value of or chipping, pressing, drying, and fresh cassava by processing it into milling (Figure 1). These new flour. The project was conducted technologies were introduced, by in three phases. demonstration, to farmers, farmer groups, and members of the Village Introducing cassava processing Unit Cooperative, or Koperasi Unit equipment Desa (KUD). These people assessed the technologies and were then Processing equipment was trained in their use. Cassava flour is demonstrated to farmers to arouse used to substitute wheat flour in the interest in cassava flour making of such foods as pancakes, production, encourage an cookies, cheese sticks, and putu ayu. increased working capacity and product quality, and promote the The cassava flour industry was development and manufacture of developed in rural areas as a processing equipment in rural three-level system (Figure 2). On areas. The equipment introduced the first level, the individual farmer and demonstrated included slicers, produced cassava flour, and carvers, graters, and presses. processed and marketed it himself. On the second level, the farmer The Kejobong KUD, in group performed these activities. particular, received, from the On the third level, the KUD not only Government, equipment with a produced cassava flour, but also daily capacity to process 10 t of received it from farmers or farmer cassava roots into flour. groups, and then sold it to food industries and middlemen.
387 Cassava Flour and Starch: Progress in Research and Development
Triguna (slicer/chipper/ rasper, used by individual farmer)
Press
Mesra 1 (rasper/slicer, used by farmer group)
OR
Peeled Apessi (dryer) cassava
OR
Mesra 2 (rasper/slicer, used by KUD)
Mill
Packer
Figure 1. Cassava flour production in Kebojong Subdistrict, Central Java, Indonesia. (KUD = Village Unit Cooperative.)
Cassava flour production flour, which was processed to cookies and pancakes. Farmer Flour production would help sell groups produced 1 t of cassava flour cassava when prices are low and and cooperatives 5 t. They sold it to demand from tapioca factories is also food industries and middlemen. small. The major problems of cassava flour production at all three levels were In 1992, individual farmers found in marketing. produced about 300 kg of cassava
388 Developing the Cassava Flour Industry in Rural Areas...
Cassava Tapioca producer factory
Fresh cassava processing I. Farmer Cassava flour Food production processing
Fresh cassava processing
II. Farmer Consumer group Cassava flour Food production processing
III. Cooperative Cassava flour (KUD) production
Entrepreneur Processor
Export
Figure 2. Developing an agroindustry based on cassava flour production in rural areas of Indonesia. (KUD = Village Unit Cooperative.)
Food technology and cassava flour Assessing the Development of use the Cassava Flour Agroindustry Marketing and food technology are important in the successful Developing the cassava flour development of a cassava flour agroindustry in rural areas was industry. Successful marketing is expected to extend cassava marketing influenced by product utility and and agroindustrial development in requisites for quantity and quality. rural areas, and to increase farmers’ Developments in food technology income. The project was evaluated increases opportunities for marketing from May to September 1992. cassava flour. Outlets for the flour are food, chemical, and other The price of fresh cassava during industries, household consumption, May and June 1993 in Kejobong and traders (middlemen, retailers, ranged from Rp 50 to Rp 60/kg, and and exporters). Such developments that of cassava flour ranged from in food marketing and technology Rp 250 to Rp 350/kg. In May and have yet to arrive in Kebojong June 1992, the typical farmer Subdistrict. produced 200 kg of cassava flour,
389 Cassava Flour and Starch: Progress in Research and Development selling it to food industries. The References typical farmer group produced 500 kg of cassava flour, selling it to Affandi, M. 1986. Agricultural development feed industries. The KUD, however, in Indonesia. Central Research did not produce cassava flour, not Institute for Food Crops (CRIFC), Bogor, Indonesia. finding it profitable. CBS (Central Bureau of Statistics). 1989. The price of cassava roots Food balance sheet in Indonesia, increased from Rp 70-90/kg in 1989. Jakarta, Indonesia. August-October 1993 to ______. 1991. Food balance sheet in Rp 95-105/kg in November 1993. Indonesia, 1989-1990. Jakarta, Farmers and farmer groups therefore Indonesia. found cassava flour production unprofitable. Other farmers used ______. 1992. Food balance sheet in cassava for feed and food. The Indonesia, 1990-1991. Jakarta, Indonesia. typical farmer would use 5-10 kg/day of dried cassava to feed Pabindru, M. 1989. Government policy in sheep and 40-50 kg/day for cantir production of cassava in Indonesia. production. In: Proceedings of a national seminar on the Effort to Increase the Added Value of Cassava. Agriculture The problem Faculty, Padjadjaran University, Bandung, Indonesia. Despite the low prices (Rp 50 to Rp 60/kg) farmers said they had no Rusastra, I. W. 1988. Study on aspects of problem marketing cassava roots. national production, consumption and marketing of cassava. Agric. Res. In contrast, producers explained Dev. J. (Indones.) 7:57-63. they had problems marketing cassava flour because it is a new SFCDP (Secondary Food Crops Development product for which food processing Project). 1990. Vademekum Palawija technology has not yet been 2. Ubikayu dan Ubijalar. (Maize, cassava and sweet potato). Direktorat developed, and of which few Jendral Peranian Tanaman Pangan. consumers know much about. SFCDP and United States Agency for International Development (USAID). Jakarta, Indonesia.
Summary Tjahjadi, C. 1989. Utilization of cassava as raw material of foods. In: Proceedings (1) Farmers, farmer groups, and of a national seminar on the Effort to KUDs had no experience in Increase the Added Value of Cassava. marketing cassava flour. Agriculture Faculty, Padjadjaran University, Bandung, Indonesia. (2) Processors and consumers lacked information on cassava Wargiono, J. 1988. Agronomic practices in processing technology and flour major cassava growing areas of use. Indonesia. In: Howeler, R. H. and (3) Appropriate cassava flour Kawano, K. (eds.). Cassava breeding and agronomy research in Asia: processing technology must be proceedings of a regional workshop, developed if the cassava flour Rayong, Thailand. CIAT, Cali, industry is to develop in rural Colombia. p. 185-204. areas. (4) Further research is needed on cassava flour use.
390 Developing the Cassava Flour Industry in Rural Areas...
391 APPENDICES Appendix I: List of Participants
APPENDIX I
LIST OF PARTICIPANTS1
Argentina Chuzel, Gerard Investigador, CIRAD/SAR-UNESP de Fabrizio, Susana Jefe, Laboratorio de Microbiología de Takitane, Isabel Cristina Alimentos Professor Assistente UBA/FCEYN Vilpoux, Olivier Pab. II Piso 3 Departamento de Tecnología Ciudad Universitaria Casilla Postal 1428 Facultad de Ciências Agronómicas Buenos Aires UNESP Tel.: (54-1) 7820529 Caixa Postal 237 Fax: (54-1) 3313272 Fazenda Experimental Lageado CEP 1860 Botucatu, São Paulo Austria Tel./Fax: (55-149) 213438, 213883 Telex: 0142107 Van Zanten, Leonard Technical Officer Cabello, Claudio Joint FAO/IAEA Division Professor Assistente RIF UNESP P.O. Box 200, A-1400 Rua Luiz Edmundo Coube, 1 Vienna Caixa Postal 473 Tel.: (43-1) 23601617 17033-360 Bauru, São Paulo Fax: (43-1) 234564 Tel.: (55-142) 302111 Telex: 142-312 FEBU
Belgium Garcia, Edivaldo Antonio Pierreux, Frédéric Professor Assistente IPESAT du Hainaut Faculdade de Medicina Veterinaria e Ath Zootecnia UNESP Caixa Postal 502 Brazil 18618-000 Botucatu, São Paulo UNESP Tel.: (55-149) 213883 R.185 Fax: (55-149) 213883 R.180 Bicudo, Silvio José Professor Assistente Morães, Iracema Professor Titular Cereda, Marney Pascoli UNESP Investigadora Rua Cristovão Colombo, 2265 Caixa Postal 136 1. Most acronyms are explained in the “List of 15054000 S. José do Rio Preto, São Paulo Acronyms and Abbreviations Used in Text,” Tel.: (55-192) 244966 ext. 64 p. 402. Fax: (55-192) 410527
393 Cassava Flour and Starch: Progress in Research and Development
Others Ospina, Bernardo CIAT-EMBRAPA Amante, Edna Regina EMBRAPA/CNPMF Vice-Chefe, Departamento/Coordenadora Rua EMBRAPA, s/n de Extenias Caixa Postal 007 UFSC 44.380 Cruz das Almas, Bahia Rodôvia Adman, Gonzaga, Km. 03 Itacorubi Tel.: (55-75) 7212120 88034-001 Florianópolis, Santa Catarina Fax: (55-75) 7211118 Tel.: (55-482) 344888 Fax: (55-482) 342014 Sarmento, Silene Bruder Professor Assistente Cintra, Odorico L. ESALQ Gerente General Av. Pádua Dias 9 Fecularia Mon Sagu Caixa Postal 9 Rua Dom Aquino No. 506-Centro 13400 Piracicaba, São Paulo 79025000 Campo Grande, Mato Grosso do Tel.: (55-194) 294150 Sul Tel.: (55-67) 3824502, 7215225 Soccol, Carlos Ricardo Fax: (55-67) 3824502 Professor UFPR Demiate, Ivo Mottin Centro Politécnico/Jardim das Américas Professor Caixa Postal 19011 81531-970 Curitiba, Paraná Wosiacki, Gilvan Tel.: (55-41) 3662323 R.285 Professor Titular Fax: (55-41) 2660222 UEPG Praça Santos Andrade, s/n Takahashi, Mario Caixa Postal 992 Investigador 8410-340 Ponta Grossa, Paraná IAPAR Tel.: (55-422) 252121 Estação Experimental de Paranavai Telex: 442 242 UEPG BR Caixa Postal 564 Fax: (55-442) 237708 87701-970 Paranavai, Paraná Tel.: (55-444) 231157 Lorenzi, José Osmar Fax: (55-444) 231607 IAC Av. Barão de Itapura 1481 Caixa Postal 28 Canada 13.001.970 Campinas, São Paulo Tel.: (55-192) 419057 Edwardson, Bill Senior Program Specialist Mello, Fabio Environment and Natural Resources Pesquisador IDRC UEPG 250 Albert Street Praça Santos Andrades, s/n P.O. Box 2500 Caixa Postal 992/993 KIG 3H9 Ottawa, Ontario 84.100.000 Ponta Grossa, Paraná Tel.: (613) 2366163 Ext. 2215 Tel.: (55-422) 252121 R.164 Telex: 0533753 Telex: 442 242 UEPG BR Fax: (613) 5677749 Fax: (55-442) 237708 E-mail: [email protected] de Morães, Flávio Faria Fitzpatrick, Dennis Professor da Graduação e Pós-graduação Professor and Head of Department Departamento de Ingeniería Química Foods and Nutrition Department UEM University of Manitoba Av. Colombo 3690 R3T 2N2 Winnipeg, Manitoba 87020.900 Maringá, Paraná Tel.: (204) 4748080 Tel.: (55-442) 264004 Fax: (204) 2755299 Telex: 442198 E-mail: Fax: (55-442) 222754 [email protected]
394 Appendix I: List of Participants
China Sánchez Rodríguez, Jaime Profesor Jin Shu-Ren Research and Management UNIVALLE NCTDC Apartado Aéreo 25360 Guchen Road 4-2 Cali, Valle del Cauca Nanning, Guangxi Tel.: (57-2) 3307285, 3393041 Tel.: (86-771) 552730 ext. 133 Fax: (86-771) 562417 Fax: (57-2) 3302479
Alazard, Didier Colombia Investigador, ORSTOM
PROPAL S.A. Raimbault, Maurice Investigador, ORSTOM Gutiérrez Herrera, Meyer Ingeniero de Proceso UNIVALLE PROPAL S.A. Apartado Aéreo 32417 Apartado Aéreo 4412 Cali, Valle del Cauca Cali, Valle del Cauca Tel.: (57-2) 6682594 Tel.: (57-2) 4425757 Ext.323 Fax: (57-2) 6682757 Fax: (57-2) 4425769
Meléndez Santacruz, Guillermo Others Gerente, Area Departamento Técnico PROPAL S.A. Barberi Ramos, Julio Darío Planta No. 2 Gerente Caloto, Cauca Productos La Niña Tel.: (57-9282) 82133 Apartado Aéreo 1422 Pereira, Risaralda Or Tel.: (57-963) 325269, 228073 Apartado Aéreo 4412 Cali, Valle del Cauca Blanco Arango, Héctor Tel.: (57-2) 4425757 Gerente, Proyecto Carbohidratos y Celulosas ARPISOL LTDA. UNIVALLE Carrera 100 No. 42A-20 Apartado Aéreo 80827 Aguinaga, Asunción Santafé de Bogotá, D.C. Jefe, Sección de Ciencia y Tecnología de Tel.: (57-91) 4158025/29 Alimentos Fax: (57-91) 4150830 Castañeda Andrade, Jesús David Jefe, Departamento de Diseño y Cifuentes Arara, Porfirio Procesos de Manufactura Carretera Panamericana Mondomo, Cauca Duque Santa, Waldo Tel.: (57-928) 299085 Director, Especialización Maquinaria Agroindustrial Duque Vargas, Amparo Fernández, Alejandro Control de la Contaminación Recursos Profesor Titular Hídricos Sección de Ciencia y Tecnología de CVC Alimentos Carrera 56 No. 11-36 Apartado Aéreo 2366 Moreno Santander, Martín Alonso Cali, Valle del Cauca Proyecto Almidón Agrio CIAT-UNIVALLE Tel.: (57-2) 3396671 de Stouvenel, Aida Rodríguez Profesora
395 Cassava Flour and Starch: Progress in Research and Development
Durán Restrepo, María Victoria Rubiano Mejía, Luz Elena Unión Europea-Delegación de la Comisión Jefe, Investigación y Desarrollo de Europea Nuevos Productos Calle 97 No. 22-44 Santafé de Bogotá, D.C. Companía Nacional de Levaduras, Tel.: (57-91) 2369040, 2564828 LEVAPAN S.A. Avenida de las Américas No. 40-81 Figueroa Sánchez, Francisco José Santafé de Bogotá, D.C. Presidente Tel.: (57-91) 2684299, 2683651 Fax: (57-91) 2681983 Sánchez Arrieta, Carlos Alberto Asesor Técnico Idárraga, Gloria Amparo Jefe, Investigación y Desarrollo Sarria Nuñez, Helberth Productos Yupi S.A. Gerente Regional/Vicepresidente Calle 70 No. 3N-74 Cali, Valle del Cauca FUNDIAGRO Tel.: (57-2) 6644330 Carrera 54 No. 55-127, Oficina 905 Fax: (57-2) 6644379 Barranquilla, Atlántico Tel.: (57-958) 411306 Jaramillo Diaz, Hebert Jefe del Area García Millán, Arbey Universidad Autónoma de Occidente Jefe de Planta Calle 9B No. 29A-67 “RICOPAN” Panadería El Porvenir Cali, Valle del Cauca Carrera 2C No. 30-35 Tel.: (57-2) 5565444 Apartado Aéreo 5384 Cali, Valle del Cauca Lozano, Alvaro Figueroa Tel.: (57-2) 4445544 Gerente, Investigación y Desarollo Gómez Botero, Claudia Quintero Muñoz, Claudia I. Directora, Investigación y Desarrollo Asistente, Investigación y Desarrollo RICARONDO S.A. Calle 31 No. 2-80 Industrias de Maíz, MAIZENA S.A. Apartado Aéreo 4842 Carrera 5A No. 52-56 Cali, Valle del Cauca Apartado Aéreo 6560 Tel.: (57-2) 4422637 Cali, Valle del Cauca Tel.: (57-2) 4474853, 4470914 González de Duque, Olga Lucía Fax: (57-2) 4477477 Gerente, Departamento Técnico y Desarrollo Mejía Gómez, Jaime Arturo Gerente Operativo Reyes Madriñan, Francisco José Productos Alimenticios Crunch S.A. Asesoría y Mantenimiento Carrera 43A No. 61 Sur 152, Local 116 Sabaneta, Antioquia Colombiana de Almidones y Apartado Aéreo 8561 Derivados S.A. Medellín, Antioquia Calle 16 Norte No. 6N-21 Tel.: (57-94) 2880254 Cali, Valle del Cauca Fax: (57-94) 2882913 Tel.: (57-2) 6681287 Ruíz Cabrera, Ricardo Guzmán Roa, Néstor Gonzalo Coordinador, Departamento de Gerente de Marca Agroindustria CETEC-SEDECOM Diagonal 26A No. 26-94 San Fernando, Cali, Valle del Cauca Tel.: (57-2) 5564809
396 Appendix I: List of Participants
Sadovnik, Alejandra Delgado Castro, Plinio Administradora Promotor
Sadovnik Sánchez, Hardy Alfonso Ruiz Chévez, Vicente Gerente Director Técnico
YUCA LTDA. UATAPPY Avenida 5 Norte No. 51-05 Calle Olmedo y 9 de Octubre Cali, Valle del Cauca Calderón, Porto Viejo, Manabí Tel./Fax: (593-4) 637240 Silva Bernal, John Edgar Cantos Sornoza, Gerente, SIMARKS Enrique Juvan Calle 90 No. 40-82 Técnico de Producción Apartado Aéreo 251789 Santafé de Bogotá, D.C. Palacios Delgado, John Herbidson Tel.: (57-91) 6101028 Administrador General
Zambrano Sarmiento, Francy Magdalena FACE Ingeniera de Alimentos Km. 101/2 Vía Manta-Montecristi Diagonal 103 No. 57-49 Apartado 13-5-4821 Santafé de Bogotá, D.C. Montecristi, Manabí Tel.: (57-91) 7110021, 535944 Tel.: (593-4) 606399 Fax: (593-4) 606109
Carpio, Cecilia Costa Rica Asistente de Investigación Blanco-Metzler, Adriana Instituto de Investigación Tecnológica Jefe, Unidad de Tecnología Nutricional EPN INCIENSA Andalucia s/n y Veintimilla Apartado 4, Tres Ríos Quito, Pichincha Tel.: 506 799911 Tel.: (593-2) 507138 Fax: 506 795546 Fax: (593-2) 507142
Boucher, François Egüez, Carlos Director Ejecutivo Coordinador, Programa de Yuca IICA/PRODAR FUNDAGRO Casilla Postal 55-2200, Coronado Moreno Bellido 127 y Amazonas Tel.: 506-290222 Apartado 17-16-219 Fax: 506-294741, 292659 Quito, Pichincha Telex: 2144 IICA CR Tel.: (593-2) 220557, 220533 E-mail: Fax: (593-2) 507442 FBoucher@UCRVM2@Bitnet Evans, Cody Laboucheix, Jean Manager of Operations Delegado para América Latina y el Caribe Representante del CIRAD ante el IICA Evans, Edward 200 m. al Sur de la Iglesia de San Pedro Compañía Ganadera Manipili Frente cost. Oeste Esc. Roosevelt Apartado 17-01-3214 Apartado 1127-2050 San Pedro Quito, Pichincha San José Tel.: (593-2) 2570177, 2570768 Tel.: (506) 255972 Telex: 22368 ADMINED Fax: (506) 250940 Fax: (593-2) 2570964
Intriago Vera, Solanda Elina Ecuador Gerente ATAPY-San Vicente Caballero Vera, Hernán Humberto Calderón, Porto Viejo Estudiante Tel.: (593) 637240
397 Cassava Flour and Starch: Progress in Research and Development
Poats, Susan V. Sautier, Denis Pierre-Jean Anthropologist, Chercheur CIAT-FUNDAGRO Project Moreno Bellido 127 y Mariano de Jesús Zakhia, Nadine Casilla 17-16-219 Chercheur Quito, Pichincha Tel.: (59-32) 220533 CIRAD/SAR Fax: (59-32) 507422 2477 Avenue du Val de Montferrand BP 5035 Ruales, Jenny 34032 Montpellier, Cedex 1 Profesor Principal Tel.: (33) 67615707 EPN Fax: (33) 67414015 Isabel La Católica y Veintimilla Hebert, Apartado 17012759 Jean Paul Quito, Pichincha ENSIA/SIARC Tel.: (593-2) 507138 1101 Avenue Agropolis Fax: (593-2) 507142 BP 5098 34032 Montpellier, Cedex 1 Verdesoto Medrano, Lécide Uvaldino Tel.: (33) 67617051 Coordinador, Proyecto de Yuca de Fax: (33) 67410232 Esmeraldas Mestres, UAPPY-Esmeraldas Christian Avenida Olmedo entre 10 de Agosto y CIRAD/CA Rocafuerte 73 rue Jean François Bretan Esmeraldas, Esmeraldas 34032 Montpellier, Cedex 1 Tel.: (593-2) 713869 Pourquié, Jacques Professeur INA-PG France 16 Rue Claude Bernard Brauman, Alain 75231 Paris, Cedex 05 ORSTOM Tel.: (33-1) 44081830 213 Rue Lafayette Fax: (33-1) 44081700 75010 Paris Tel.: (33-1) 48037777 Ghana Safo-Kantanka, della Valle, Guy Rene Noel Osei Ingeniero de Investigación, Tratamientos Crop Science Department Físicos de Almidones University of Science & Technology Centre de recherche agro-alimentaires Kumasi INRA Tel.: (233-51) 53519 BP 527 Fax: (233-51) 3137 44026 Nantes Tel.: (33) 4067 8000 Fax: (33) 4067 8005 Honduras Santos Sosa, Samuel Giraud, Eric Responsable, Proyecto de Yuca (Utilización) Ingénieur Fundación Friedrich Ebert ORSTOM Colonia Humaya 2a. Calle No. 2401 2051 Avenue du Val de Montferrand Apartado No. 1701 BP 5045 Tegucigalpa 34032 Montpellier, Cedex 1 Tel.: (504) 332753 Tel.: (33) 67617400, 67617575 Fax: (504) 332800 Fax: (33) 67547800
Griffon, Dany Deputy Director, Program and Development
398 Appendix I: List of Participants
India Pereira Pacheco, Fabiola Esther Responsable, Laboratorio de Ciencia de los Moorthy, Nayarana Alimentos Senior Scientist Facultad de Ingeniería Química CTCRI Av. Juárez No. 421 Cd. Industrial Trivandrum, Kerala Casilla Postal 1226-A Tel.: 91-448554 97288 Mérida, Yucatán Tel.: (52) 460981 Indonesia Fax: (52) 460994 Damardjati, Djoko S. Nicaragua Director BORIF Bosche, Paul JL. Tentara Pelajar 3A Director Ejecutivo Bogor 16111 Yuca Centroamericana S.A., YUCASA Tel./Fax: 62-251-333440 No. 10 Planes Altamira Apartado A-179 Managua Kenya Tel./Fax: (505-2) 784915 Mbugua, Samuel Teaching and Research Briceño Lovo, Milton Marcelo Department of Food Technology & Nutrition Director, Control Industrial College of Agriculture & ET Sciences University of Nairobi Miranda Astorga, Lester José P.O. Box 29053 Gerente General Nairobi Tel.: 254-2-632211, 632141, Yuca Centroamericana S.A., YUCASA 632401 Km. 31 Carretera vieja a León Fax: 254-2-630172 Tel./Fax: (505-2) 784915
Malawi Nigeria Saka, J. D. K. Bokanga, Mpoko Senior Lecturer in Chemistry Biochemist Chemisty Department IITA Chancellor College PMB 5320, Ibadan University of Malawi Tel.: (234-22) 400300 P.O. Box 280 Telex: 31417 TOPIP NG Zomba Tel.: (265) 522222, 52327 Paraguay Telex: 44742 CHANCOL MI Fax: (265) 522046, 523021 Hüg de Belmont V., Carlos A. Administrador de Planta/Asistente de Mexico Producción FUNDAIN Guyot, Jean-Pierre Ayolas 451, Edificio Capital, 4o. Piso Head, Research Programme Asunción Central ORSTOM Tel.: (595-21) 442-518/9 Cicerón 609 Fax: (595-21) 442-520 11530 México DF Tel.: (55-5) 6807688 Peru Monroy Rivera, José Alberto Espínola de Fong, Nelly Profesor Investigador Fisióloga Instituto Tecnológico de Veracruz CIP Circunvalación Norte e Icazo Avenida La Universidad s/n Apartado 1420 Casilla 5969, Lima 12 Veracruz Tel.: (51-14) 366920 Tel./Fax: (52-29) 345701 Fax: (51-14) 351570
399 Cassava Flour and Starch: Progress in Research and Development
Rodríguez Zevallos, Antonio Ricardo Trinidad and Tobago Jefe, Centro de Producción Agroindustrial Universidad Nacional “Pedro Ruiz Gallo” Badrie, Neela Ciudad Universitaria Food Technology Unit Lambayeque, Lambayeque Department of Chemical Engineering Tel.: (51-074) 282787 UWI St. Augustine, Trinidad Salas Domínguez, Sonia Tel.: (1-809) 6632001/2007 Jefe, Proyectos Fax: (1-809) 6624414 Cáritas del Perú Calle Omicrón 492 Callao United Kingdom Tel.: (51-14) 640299 Fax: (51-14) 642595 Trim, David S. Agroprocessing Group Salas Valerio, Walter Francisco Wenham, June Elizabeth Jefe, Departamento Ingeniería de Alimentos Post-Harvest Horticulture UNALM Av. La Universidad s/n, La Molina NRI Casilla Postal 456 Central Avenue Lima Chatham Maritime, Kent ME4 4TB England Tel.: (44-0634) 880088 Philippines Telex: 236907/8 LDN Fax: (44-0634) 880066/77 Tan, Daniel Leslie Agricultural Engineer PRCRTC-ViSCA Venezuela Baybay, Leyte, Zip Code 6521-A Fax: (63-2) 588692 INDELMA C.A.
Tanzania Bustamante Valero, Lizardo de Jesús Gerente, Planta Industrial Mlingi, Nicholas L. V. Senior Food Chemist Contreras Vega, José Luis Tanzania Food and Nutrition Centre Superintendente, Almidones Modificados P.O. Box 977 INDELMA C.A. Dar es Salaam Km. 1 La Encrucijada vía Turmero Tel.: (255-51) 29621, 74107 Turmero, Aragua Fax: (255-51) 44029 Tel.: (58-04) 4632320
Perdomo Ramos, María Teresa Thailand Representante Técnico INDELMA C.A. Maneepun, Saipin Av. Lecuna Esquina de Petión Researcher Edificio El Aguila, San Agustín del Sur IFRPD 122 Caracas Kasetsart University Tel.: (58-2) 5762133 P.O. Box 170 Telex: 21308 ARCIA VC Bangkok 10400 Fax: (58-2) 5736712 Tel./Fax: (66-2) 561 1970
Titapiwatanakun, Boonjit Assistant Professor Kasetsart University Bangkhen, Bangkok 10903 Tel.: (66-2) 561 3467 Fax: (66-2) 561 3034
400 Appendix I: List of Participants
Others Ayala Aponte, Alfredo Adolfo Research Assistant Faroux, Gerard Delegado Regional de Cooperación Bellotti, Anthony Países Andinos Entomologist Embajada de Francia Calle Madrid con Av. Trinidad Best, Rupert Las Mercedes-Caracas Leader, Cassava Program Apartado 62324, Caracas 1060-A Tel.: (58-2) 9937448 Bonierbale, Merideth Fax: (58-2) 9935256 Geneticist González Parada, Zurima Mercedes Brabet, Catherine Profesor/Investigador Visiting Researcher ICTA-UCV/FAC Calle Suapure Lomas de Bello Monte Dufour, Dominique Apartado 47.097, Caracas 1041-A Cassava Utilization Specialist Tel.: (58-2) 7524403 CIRAD/SAR-CIAT Fax: (58-2) 7523871 El-Sharkawy, Mabrouk Pacheco Cedeño, Simón José Physiologist Presidente Asociación de Productores de Yuca Henry, Guy Transversal 11 No. 417, Urb. Fundemos I Economist Maturín, Monagas Tel.: (58-91) 512550 Jones, Debbie Fax: (58-91) 412441 Chemical Engineer
López Alarcón, John Mario Vietnam Student Dang Thanh Ha Lecturer Mosquera Palacio, Liliana Department of Agricultural Economics Research Assistant University of Agriculture and Forestry Ho Chi Minh City Murcia, Luzmila Tel.: (84) 8-966780 Technician Fax: (84) 8-231541 O’Brien, Gerard Michael Food Scientist Zambia Orozco Marmolejo, Oswaldo Namposya, Rebecca Technician Farming Systems Nutritionist Farming Systems Research Team Ostertag, Carlos Felipe Adaptive Research Planning Team Associate Mt. Makulu Research Station P/Bag 7, Chilanga Pérez Valdés, Diego Tel.: (26-01) 278514 Research Assistant Fax: (26-01) 213927 Salcedo Bonilla, Enna Elena Technician CIAT Sánchez, Teresa Apartado Aéreo 6713 Research Assistant Cali, Colombia Tel.: (57-2) 4450000 Scowcroft, William Fax: (57-2) 4450073 Deputy Director General
Alarcón Morante, Freddy Thro, Ann Marie Assistant Coordinator, CBN
401 Cassava Flour and Starch: Progress in Research and Development
APPENDIX II
LIST OF ACRONYMS AND ABBREVIATIONS USED IN TEXT
Acronyms BFAD Bureau of Food and Drugs, the Philippines AACC American Association of Cereal Chemists, USA BNH Banco Nacional de Habitação, Brazil ABAM Associação Brasileira dos Produtores de Amido de BOI Board of Investment, Mandioca, Brazil Thailand
ABES Associação Brasileira de BORIF Bogor Research Institute for Engenharia Sanitária, Food Crops, Indonesia Brazil CA Département des cultures ACDI Agricultural Cooperative annuelles (CIRAD) Development International, Colombia CBN Cassava Biotechnology Network, based in Colombia AFST Association of Food Science Technology, India CBS Central Bureau of Statistics, Indonesia ANPPY Asociación Nacional de Productores y Procesadores CDA Cooperative Development de Yuca, Colombia Authority, the Philippines
AOAC Association of Official CDF Countrywide Development Analytical Chemists, USA Fund, the Philippines
APPYs Asociaciones de CENDES Centro de Desarrollo, Productores y Procesadores Ecuador de Yuca, Ecuador CEPAGRO Centro Estadual de ASOCOSTA Asociación de Cooperativas Pesquisa Agronómica, de la Costa, Colombia Brazil
ASTM American Society for CERAT Centro Raizes Tropicais Testing and Materials, (UNESP) USA CETEC Corporación para Estudios ATAPYs Asociaciones de Interdisciplinarios y Trabajadores Agrícolas y Asesorías Técnicas, Productores de Yuca, Colombia Ecuador
402 Appendix II: List of Acronyms and Abbreviations Used in Text
CETESB Companhia de Tecnologia DEMSA Derivados del Maiz, S. A. de Saneamento Ambiental, (private company), Peru Brazil DEPD Department of Economic CGPRT Center for Research and Planning and Development of Coarse Development, Malawi Grains, Pulses, Roots and Tuber Crops in the Humid DGRST Direction générale de la Tropics of Asia and the recherche scientifique et Pacific, Indonesia technique, Congo
CIP Centro Internacional de la DOLE Department of Labor and Papa, based in Peru Employment, the Philippines CNPMF Centro Nacional de Pesquisa de Mandioca e DRI Fondo de Desarrollo Rural Fruticultura (EMBRAPA) Integrado, Colombia
CONAB Companhia Nacional de DTI Department of Trade and Abastecimento, Brazil Industry, the Philippines
COOPEMUBA Cooperativa de EEC European Economic Productores de Mandioca Community, now the EU de Ubajara, Brazil EMATER Empresa de Assistência COOPROALGA Cooperativa de Técnica e Extensão Rural, Productores de los Brazil Algarrobos, Colombia EMATER-CE Empresa de Pesquisa, COPROMA Cooperativa de Assistência Técnica e Productores de Mandioca Extensão Rural do Ceará, de Acarau, Brazil Brazil
CORAF Conférence des EMBRAPA Empresa Brasileira de responsables de Pesquisa Agropecuária, recherche agronomique en Brazil Afrique de l’Ouest et du Centre ENSAM Ecole nationale supérieure agronomique de CPC Corn Products Company, Montpellier, France USA ENSBANA Ecole nationale supérieure CRIFC Central Research Institute de biologie appliquée à la for Food Crops, Indonesia nutrition et l’alimentation, France CRVZ Centre de recherche vétérinaire et zootechnique ENSIA Ecole nationale supérieure (DGRST) des industries agricoles et alimentaires, France CTCRI Central Tuber Crops Research Institute, India EPACE Empresa de Pesquisa Agropecuária do Ceará, CVC Corporación Autónoma Brazil Regional del Valle del Cauca, Colombia EPN Escuela Politécnica Nacional, Ecuador DANE Departamento Administrativo Nacional de ERS Economic Research Estadística, Colombia Service (USDA)
403 Cassava Flour and Starch: Progress in Research and Development
ESAL Escola Superior de IAC Instituto Agronômico de Agronômia de Lavras, Campinas, Brazil Brazil IADS International Agricultural ESALQ Escola Superior de Development Service, New Agricultura “Luiz de York, USA Queiroz”, Brazil IAEA International Atomic EU European Union, often Energy Agency, Italy known as the EC or EEC IAPAR Instituto Agronômico do FAC Facultad de Ciencias (UCV) Paraná, Brazil
FACE Fundación Adelanto IARCs International Agricultural Comunitario, Ecuador Research Centers of the Consultative Group on FAO Food and Agriculture International Agricultural Organization of the United Research (CGIAR), USA Nations, Italy IBGE see FIBGE FCA Faculdade de Ciências Agronômicas (UNESP) IBPGR International Board for Plant Genetic Resources, FIBGE Fundação Instituto now IPGRI Brasileiro de Geografia e Estatística, Brazil (also IBRD International Bank for IBGE) Reconstruction and Development (also known FODERUMA Fondo para el Desarrollo as the World Bank), USA Rural del Ministerio de Agricultura, Ecuador IBSRAM International Board of Soil Resources and FUNDAGRO Fundación para el Management, Thailand Desarrollo Agropecuario, Ecuador ICA Instituto Colombiano Agropecuario FUNDAIN Fundación Paraguaya de Apoyo a la Agroindustria, ICH International Child Health Paraguay Unit, Sweden ICMSF International Commission FUNDIAGRO Fundación para la on Microbiological Investigación y el Specifications for Foods, Desarrollo de Tecnologías UK Apropiadas al Agro, Colombia ICONTEC Instituto Colombiano de Normas Técnicas GATT General Agreement on Tariffs and Trade, EU ICTA Instituto de Ciencia y Tecnología Agrícolas, GBSA Laboratoire de Guatemala microbiologie et biochimie industrielles of the IDRC International Development Université Montpellier II, Research Centre, Canada France IFRPD Institute of Food Research GNCTDC Guangxi Nanning Cassava and Product Development Technical Development of Kasetsart University, Center, China (also Thailand NCTDC)
404 Appendix II: List of Acronyms and Abbreviations Used in Text
IFS International Foundation ITCF Institut technique des for Science, Sweden céréales et des fourrages of the Céréaliers du France IIAP Instituto de Investigaciones de la KUD Koperasi Unit Desa (Village Amazonía Peruana Unit Cooperative), Indonesia IICA Instituto Interamericano de Cooperación para la MAE Ministère des Affaires Agricultura, Costa Rica Etrangères, France
IIED International Institute for MAG Ministerio de Agricultura, Environment and Ecuador Development, UK MARA Ministério da Agricultura e IITA International Institute of Reforma Agrária, Brazil Tropical Agriculture, Nigeria MARCA Mabagon Root Crop Association, the INA-PG Institut national Philippines agronomique, Paris-Grignon MIPRE Ministerio de la Presidencia, Peru INCIENSA Instituto Costarricense de Investigación y Enseñanza MOAC Ministry of Agriculture and en Nutrición y Salud, Cooperatives, Thailand Costa Rica MOI Ministry of Industry, INDELMA C.A. Industrias del Maíz C.A., Thailand Venezuela NAPHIRE National Postharvest INIA Instituto Nacional de Institute for Research and Investigación Agraria, Peru Extension, the Philippines
INIAP Instituto Nacional de NCTDC see GNCTDC Investigaciones Agropecuarias, Ecuador NRI Natural Resources Institute, UK INN Instituto Nacional de Nutrición, Venezuela ORSTOM Institut français de recherche scientifique pour INRA Institut national de le développement en recherche agronomique, coopération, France France PCARRD Philippine Council for IPESAT Institut provencial Agriculture and Resources d’enseighement superieur Research and Development agronomique et technique du Hainaut, Belgium PMO Prime Minister’s Office, Tanzania IPGRI International Plant Genetic PRCRTC Philippine Root Crop Resources Institute, Italy Research and Training Center ISNAR International Service for National Agricultural Research, the Netherlands PRODAR Programa Cooperativo de Desarrollo Agroindustrial ISU Isabela State University, Rural, Costa Rica the Philippines
405 Cassava Flour and Starch: Progress in Research and Development
PRONAA Programa Nacional de UATAPPY Unión de Asociaciones de Alimentación, Peru Trabajadores Agrícolas, Productores y PROPAL S.A. Productora de Papeles S.A., Procesadores de Yuca, Colombia Ecuador
SEARCA Southeast Asian Regional UBA Universidad de Buenos Center for Graduate Study Aires, Argentina and Research in Agriculture, the Philippines UCV Universidad Central de Venezuela SECTI Secretaría Ejecutiva de Cooperación Internacional UEM Universidade Estadual de (MIPRE) Maringá, Brazil
SEDECOM Servicio de Desarrollo y UEPG Universidade Estadual de Consultoría para el Ponta Grossa, Brazil Sector Cooperativo y de Micro-Empresas, Colombia UFPR Universidade Federal do Paraná, Brazil SFCDP Secondary Food Crops Development Project, UFSC Universidade Federal de Indonesia Santa Catarina, Brazil
SIARC Section industries agricoles UNALM Universidad Nacional et alimentaires des régions Agraria “La Molina”, Peru chaudes (ENSIA) UNESCO United Nations Education, SUDENE Superintendência do Scientific, and Cultural Desenvolvimento do Organization, France Nordeste, Brazil UNESP Universidade Estadual TAPPI Technical Association of the Paulista, Brazil Pulp and Paper Industry, New York UNIVALLE Universidad del Valle, Colombia TDRI Thailand Development Research Institute USAID United States Agency for International TDRI Tropical Development and Development, USA Research Institute, UK USDA United States Department TPPIA Thai Pulp and Paper of Agriculture Industries Association UST University of Science and TTFITA Thai Tapioca Flour Technology, Ghana Industries Trade Association UTC Université de Tecnologie de Compiègne, France TTTA Thai Tapioca Trade Association UWI University of the West Indies, Trindad and UAM Universidad Autónoma Tobago Metropolitana, Mexico ViSCA Visayas State College UAPPY Unión de Asociaciones de of Agriculture, the Productores y Procesadores Philippines de Yuca, Ecuador
406 Appendix II: List of Acronyms and Abbreviations Used in Text
WAG Water Activity Group of the CNP Total cyanogenic potential European Cooperation in the Field of Science and COD Chemical oxygen demand Technical Research (investigates water content COO- Chemical symbol of of substances) double-bound carbon
WHO World Health Organization d.b. Dry basis
WIPS “Women in Postproduction DEAE Diethylaminoethyl (used in Systems,” collaborative enzyme analysis) project in the Philippines DM Dry matter
DNA Deoxyribonucleic acid Abbreviations DSC Differential scanning ALAB Amylolytic lactic acid calorimetry bacteria D.W. Devon-Watson estimate APC Aerobic plate count (statistics)
ATP Adenosine triphosphate ECU European currency unit
aw Water activities (in EU Enzyme units determining food isotherms) f.o.b. (F.O.B.) Free on board
BA Brabender amylograph FRR Financial rate of return
BE Starch-branching enzyme fwb Fresh weight basis (gene responsible for the cross linkages that form g Gravitation constant (in amylopectin) centrifuging)
BMP Bread-making potential G.A.B. The Guggenheim- Anderson-De Boer model BOD Biochemical oxygen used for describing food demand isotherms in equations
BU Brabender viscosity units GBSS Granule-bound starch (for starches) synthase (gene responsible for amylose synthesis) CAP Common Agricultural Policy of the EU GDP Gross domestic product
CCF Chlorinated cake flour g.f.b. Glucose-fermenting bacteria cDNA Complementary DNA GNP Gross national product CF Control fermentation GPI-ID Indice geral de preços- cfu Colony-forming unit demanda interna (deflator, in economics = general CG Cyanogenic glucosides price index-internal demand) c.i.f. (C.I.F.) Cost, insurance, and freight hab Habitant
407 Cassava Flour and Starch: Progress in Research and Development
HCN Hydrogen cyanide, and OD Optical density sometimes used to express cyanide content in OVL Organic volume load cassava p Pressure (used in HDPE High-density polyethylene physicochemical (used for packaging) measurements)
HFCS High fructose corn syrup, PCA Plate count analysis (for also known as isoglucose estimating microbial populations) HFS High fructose syrup PCR Polymerase chain HPLC High-performance liquid reaction chromatography PDA Potato dextrose agar ICRDPs Integrated cassava research medium and development projects PE Pectinesterase (pectin IQR Interquartile range pectylhydrolase (statistics) E.C. 3.1.1.11) kDa Kilo Dalton (measure of PG Polygalacturonase (poly molecular weight) (1,4-α-D-galacturonide) glycanohydrolase, l.a.b. Lactic acid bacteria E.C. 3.2.1.15) l.f.b. Lactate-fermenting bacteria PGL Polygalacturonate lyase
M Molecular weight pKa Negative logarithm of equilibrium constant for MDF medium density fiber board association (used for (timber) measuring acidification)
MG Minais Gerais, state of PNPG p-nitrophenol-β-D- Brazil glucopyranoside (a chromogen) MPN Most probable number (a
method of enumerating pO2 Partial oxygen pressure microorganisms) PVC Polyvinyl chloride MRS de Man-Rogosa-Sharpe agar medium R&D Research and development
MS Modified starches RAPD Random amplified polymorphic DNA MSG Monosodium glutamate RFLPs DNA restriction fragment MTBE Methyl tertiary butyl ether length polymorphisms
NaCl Common salt or sodium RMS % Relative root mean chloride square error
NGC Nonglucosidic cyanogens rpm Revolutions per minute
NGFI Nongrain feed ingredients RVA Rapid Visco Analyzer (relating to CAP) (equipment for measuring starch viscosity profiles, NGOs Nongovernmental which are expressed in organizations “RVA units”) 408 Appendix II: List of Acronyms and Abbreviations Used in Text
SDS Sodium dodecyl sulfate V Volt
SDS-PAGE SDS-polyacrylamide gel VFA Volatile fatty acids electrophoresis VSS Volatile suspended solids SF Sterile fermentation VUC Village union cooperative, TC Total cyanogen content Indonesia
TR Taxa de reajuste (after w/v Weight by volume readjustment, in economics) w.b. Wet basis
UMS Unmodified or native w/w Weight-to-weight ratio starches WSI Water solubility index UV Ultraviolet (radiation)
409 Contents
CIAT Publication No. 271
CIRAD/SAR andandand CIAT’s Communications Unit
Editing: Elizabeth L. de Páez Annie Jones
Editorial assistance: Gladys Rodríguez
Translation (six chapters): Lynn Menéndez Deborah Jones
Photography: Dominique Dufour CIAT Photographic Section
Production: Graphic Arts Unit, CIAT Alcira Arias (layout) Jorge Gallego (layout) Julio C. Martínez (cover design)
Printing: Impresora Feriva S.A., Cali
xiii